Do not use single quotes in the example config

This replaces single quotes for double quotes in the configuration
comments that refer to strings.
This was misleading since someone could took that comment as a valid
config entry, which is not.  One notable example was `backend = 'glx'`
which is not accepted by libconfig.

This also adds `;` for each default config values for consistency.

picom.sample.conf

@@ -3,8 +3,8 @@
 #################################
 
 
-# Enabled client-side shadows on windows. Note desktop windows 
+# Enabled client-side shadows on windows. Note desktop windows
-# (windows with '_NET_WM_WINDOW_TYPE_DESKTOP') never get shadow, 
+# (windows with '_NET_WM_WINDOW_TYPE_DESKTOP') never get shadow,
 # unless explicitly requested using the wintypes option.
 #
 # shadow = false
@@ -52,11 +52,11 @@ shadow-exclude = [
 ];
 
 # Specify a X geometry that describes the region in which shadow should not
-# be painted in, such as a dock window region. Use 
+# be painted in, such as a dock window region. Use
 #    shadow-exclude-reg = "x10+0+0"
 # for example, if the 10 pixels on the bottom of the screen should not have shadows painted on.
 #
-# shadow-exclude-reg = "" 
+# shadow-exclude-reg = ""
 
 # Crop shadow of a window fully on a particular Xinerama screen to the screen.
 # xinerama-shadow-crop = false
@@ -70,7 +70,7 @@ shadow-exclude = [
 # Fade windows in/out when opening/closing and when opacity changes,
 #  unless no-fading-openclose is used.
 # fading = false
-fading = true
+fading = true;
 
 # Opacity change between steps while fading in. (0.01 - 1.0, defaults to 0.028)
 # fade-in-step = 0.028
@@ -123,9 +123,9 @@ focus-exclude = [ "class_g = 'Cairo-clock'" ];
 # Use fixed inactive dim value, instead of adjusting according to window opacity.
 # inactive-dim-fixed = 1.0
 
-# Specify a list of opacity rules, in the format `PERCENT:PATTERN`, 
+# Specify a list of opacity rules, in the format `PERCENT:PATTERN`,
-# like `50:name *= "Firefox"`. picom-trans is recommended over this. 
+# like `50:name *= "Firefox"`. picom-trans is recommended over this.
-# Note we don't make any guarantee about possible conflicts with other 
+# Note we don't make any guarantee about possible conflicts with other
 # programs that set '_NET_WM_WINDOW_OPACITY' on frame or client windows.
 # example:
 #    opacity-rule = [ "80:class_g = 'URxvt'" ];
@@ -139,22 +139,22 @@ focus-exclude = [ "class_g = 'Cairo-clock'" ];
 
 
 # Parameters for background blurring, see the *BLUR* section for more information.
-# blur-method = 
+# blur-method =
 # blur-size = 12
 #
 # blur-deviation = false
 #
 # blur-strength = 5
 
-# Blur background of semi-transparent / ARGB windows. 
+# Blur background of semi-transparent / ARGB windows.
-# Bad in performance, with driver-dependent behavior. 
+# Bad in performance, with driver-dependent behavior.
 # The name of the switch may change without prior notifications.
 #
 # blur-background = false
 
-# Blur background of windows when the window frame is not opaque. 
+# Blur background of windows when the window frame is not opaque.
 # Implies:
-#    blur-background 
+#    blur-background
 # Bad in performance, with driver-dependent behavior. The name may change.
 #
 # blur-background-frame = false
@@ -168,7 +168,7 @@ focus-exclude = [ "class_g = 'Cairo-clock'" ];
 # example:
 #   blur-kern = "5,5,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1";
 #
-# blur-kern = ''
+# blur-kern = ""
 blur-kern = "3x3box";
 
 
@@ -190,17 +190,17 @@ blur-background-exclude = [
 # Specify the backend to use: `xrender`, `glx`, or `xr_glx_hybrid`.
 # `xrender` is the default one.
 #
-# backend = 'glx'
+# backend = "glx"
 backend = "xrender";
 
 # Enable/disable VSync.
 # vsync = false
-vsync = true
+vsync = true;
 
 # Enable remote control via D-Bus. See the *D-BUS API* section below for more details.
 # dbus = false
 
-# Try to detect WM windows (a non-override-redirect window with no 
+# Try to detect WM windows (a non-override-redirect window with no
 # child that has 'WM_STATE') and mark them as active.
 #
 # mark-wmwin-focused = false
@@ -210,7 +210,7 @@ mark-wmwin-focused = true;
 # mark-ovredir-focused = false
 mark-ovredir-focused = true;
 
-# Try to detect windows with rounded corners and don't consider them 
+# Try to detect windows with rounded corners and don't consider them
 # shaped windows. The accuracy is not very high, unfortunately.
 #
 # detect-rounded-corners = false
@@ -222,20 +222,20 @@ detect-rounded-corners = true;
 # detect-client-opacity = false
 detect-client-opacity = true;
 
-# Specify refresh rate of the screen. If not specified or 0, picom will 
+# Specify refresh rate of the screen. If not specified or 0, picom will
 # try detecting this with X RandR extension.
 #
 # refresh-rate = 60
-refresh-rate = 0
+refresh-rate = 0;
 
-# Use EWMH '_NET_ACTIVE_WINDOW' to determine currently focused window, 
+# Use EWMH '_NET_ACTIVE_WINDOW' to determine currently focused window,
-# rather than listening to 'FocusIn'/'FocusOut' event. Might have more accuracy, 
+# rather than listening to 'FocusIn'/'FocusOut' event. Might have more accuracy,
 # provided that the WM supports it.
 #
 # use-ewmh-active-win = false
 
-# Unredirect all windows if a full-screen opaque window is detected, 
+# Unredirect all windows if a full-screen opaque window is detected,
-# to maximize performance for full-screen windows. Known to cause flickering 
+# to maximize performance for full-screen windows. Known to cause flickering
 # when redirecting/unredirecting windows.
 #
 # unredir-if-possible = false
@@ -246,84 +246,84 @@ refresh-rate = 0
 # Conditions of windows that shouldn't be considered full-screen for unredirecting screen.
 # unredir-if-possible-exclude = []
 
-# Use 'WM_TRANSIENT_FOR' to group windows, and consider windows 
+# Use 'WM_TRANSIENT_FOR' to group windows, and consider windows
 # in the same group focused at the same time.
 #
 # detect-transient = false
-detect-transient = true
+detect-transient = true;
 
-# Use 'WM_CLIENT_LEADER' to group windows, and consider windows in the same 
+# Use 'WM_CLIENT_LEADER' to group windows, and consider windows in the same
-# group focused at the same time. 'WM_TRANSIENT_FOR' has higher priority if 
+# group focused at the same time. 'WM_TRANSIENT_FOR' has higher priority if
 # detect-transient is enabled, too.
 #
 # detect-client-leader = false
-detect-client-leader = true
+detect-client-leader = true;
 
-# Resize damaged region by a specific number of pixels. 
+# Resize damaged region by a specific number of pixels.
-# A positive value enlarges it while a negative one shrinks it. 
+# A positive value enlarges it while a negative one shrinks it.
-# If the value is positive, those additional pixels will not be actually painted 
+# If the value is positive, those additional pixels will not be actually painted
-# to screen, only used in blur calculation, and such. (Due to technical limitations, 
+# to screen, only used in blur calculation, and such. (Due to technical limitations,
-# with use-damage, those pixels will still be incorrectly painted to screen.) 
+# with use-damage, those pixels will still be incorrectly painted to screen.)
-# Primarily used to fix the line corruption issues of blur, 
+# Primarily used to fix the line corruption issues of blur,
-# in which case you should use the blur radius value here 
+# in which case you should use the blur radius value here
-# (e.g. with a 3x3 kernel, you should use `--resize-damage 1`, 
+# (e.g. with a 3x3 kernel, you should use `--resize-damage 1`,
-# with a 5x5 one you use `--resize-damage 2`, and so on). 
+# with a 5x5 one you use `--resize-damage 2`, and so on).
 # May or may not work with *--glx-no-stencil*. Shrinking doesn't function correctly.
 #
 # resize-damage = 1
 
-# Specify a list of conditions of windows that should be painted with inverted color. 
+# Specify a list of conditions of windows that should be painted with inverted color.
 # Resource-hogging, and is not well tested.
 #
 # invert-color-include = []
 
-# GLX backend: Avoid using stencil buffer, useful if you don't have a stencil buffer. 
+# GLX backend: Avoid using stencil buffer, useful if you don't have a stencil buffer.
-# Might cause incorrect opacity when rendering transparent content (but never 
+# Might cause incorrect opacity when rendering transparent content (but never
-# practically happened) and may not work with blur-background. 
+# practically happened) and may not work with blur-background.
 # My tests show a 15% performance boost. Recommended.
 #
 # glx-no-stencil = false
 
-# GLX backend: Avoid rebinding pixmap on window damage. 
+# GLX backend: Avoid rebinding pixmap on window damage.
-# Probably could improve performance on rapid window content changes, 
+# Probably could improve performance on rapid window content changes,
 # but is known to break things on some drivers (LLVMpipe, xf86-video-intel, etc.).
 # Recommended if it works.
 #
 # glx-no-rebind-pixmap = false
 
-# Disable the use of damage information. 
+# Disable the use of damage information.
 # This cause the whole screen to be redrawn everytime, instead of the part of the screen
 # has actually changed. Potentially degrades the performance, but might fix some artifacts.
 # The opposing option is use-damage
 #
 # no-use-damage = false
-use-damage = true
+use-damage = true;
 
-# Use X Sync fence to sync clients' draw calls, to make sure all draw 
+# Use X Sync fence to sync clients' draw calls, to make sure all draw
-# calls are finished before picom starts drawing. Needed on nvidia-drivers 
+# calls are finished before picom starts drawing. Needed on nvidia-drivers
 # with GLX backend for some users.
 #
 # xrender-sync-fence = false
 
-# GLX backend: Use specified GLSL fragment shader for rendering window contents. 
+# GLX backend: Use specified GLSL fragment shader for rendering window contents.
-# See `compton-default-fshader-win.glsl` and `compton-fake-transparency-fshader-win.glsl` 
+# See `compton-default-fshader-win.glsl` and `compton-fake-transparency-fshader-win.glsl`
 # in the source tree for examples.
 #
-# glx-fshader-win = ''
+# glx-fshader-win = ""
 
-# Force all windows to be painted with blending. Useful if you 
+# Force all windows to be painted with blending. Useful if you
 # have a glx-fshader-win that could turn opaque pixels transparent.
 #
 # force-win-blend = false
 
-# Do not use EWMH to detect fullscreen windows. 
+# Do not use EWMH to detect fullscreen windows.
 # Reverts to checking if a window is fullscreen based only on its size and coordinates.
 #
 # no-ewmh-fullscreen = false
 
-# Dimming bright windows so their brightness doesn't exceed this set value. 
+# Dimming bright windows so their brightness doesn't exceed this set value.
-# Brightness of a window is estimated by averaging all pixels in the window, 
+# Brightness of a window is estimated by averaging all pixels in the window,
-# so this could comes with a performance hit. 
+# so this could comes with a performance hit.
 # Setting this to 1.0 disables this behaviour. Requires --use-damage to be disabled. (default: 1.0)
 #
 # max-brightness = 1.0
@@ -335,17 +335,17 @@ use-damage = true
 
 # Set the log level. Possible values are:
 #  "trace", "debug", "info", "warn", "error"
-# in increasing level of importance. Case doesn't matter. 
+# in increasing level of importance. Case doesn't matter.
-# If using the "TRACE" log level, it's better to log into a file 
+# If using the "TRACE" log level, it's better to log into a file
 # using *--log-file*, since it can generate a huge stream of logs.
 #
 # log-level = "debug"
 log-level = "warn";
 
 # Set the log file.
-# If *--log-file* is never specified, logs will be written to stderr. 
+# If *--log-file* is never specified, logs will be written to stderr.
-# Otherwise, logs will to written to the given file, though some of the early 
+# Otherwise, logs will to written to the given file, though some of the early
-# logs might still be written to the stderr. 
+# logs might still be written to the stderr.
 # When setting this option from the config file, it is recommended to use an absolute path.
 #
 # log-file = '/path/to/your/log/file'
@@ -357,33 +357,33 @@ log-level = "warn";
 # write-pid-path = '/path/to/your/log/file'
 
 # Window type settings
-# 
+#
-# 'WINDOW_TYPE' is one of the 15 window types defined in EWMH standard: 
+# 'WINDOW_TYPE' is one of the 15 window types defined in EWMH standard:
-#     "unknown", "desktop", "dock", "toolbar", "menu", "utility", 
+#     "unknown", "desktop", "dock", "toolbar", "menu", "utility",
-#     "splash", "dialog", "normal", "dropdown_menu", "popup_menu", 
+#     "splash", "dialog", "normal", "dropdown_menu", "popup_menu",
 #     "tooltip", "notification", "combo", and "dnd".
-# 
+#
 # Following per window-type options are available: ::
-# 
+#
 #   fade, shadow:::
 #     Controls window-type-specific shadow and fade settings.
-# 
+#
 #   opacity:::
 #     Controls default opacity of the window type.
-# 
+#
 #   focus:::
-#     Controls whether the window of this type is to be always considered focused. 
+#     Controls whether the window of this type is to be always considered focused.
 #     (By default, all window types except "normal" and "dialog" has this on.)
-# 
+#
 #   full-shadow:::
-#     Controls whether shadow is drawn under the parts of the window that you 
+#     Controls whether shadow is drawn under the parts of the window that you
-#     normally won't be able to see. Useful when the window has parts of it 
+#     normally won't be able to see. Useful when the window has parts of it
 #     transparent, and you want shadows in those areas.
-# 
+#
 #   redir-ignore:::
-#     Controls whether this type of windows should cause screen to become 
+#     Controls whether this type of windows should cause screen to become
 #     redirected again after been unredirected. If you have unredir-if-possible
-#     set, and doesn't want certain window to cause unnecessary screen redirection, 
+#     set, and doesn't want certain window to cause unnecessary screen redirection,
 #     you can set this to `true`.
 #
 wintypes: