Add docs for enabling system font smoothing on macOS

alacritty_macos.yml

@@ -123,6 +123,16 @@ font:
   #
   # Thin strokes are suitable for retina displays, but for non-retina screens
   # it is recommended to set `use_thin_strokes` to `false`
+  #
+  # macOS >= 10.14.x:
+  #
+  # If the font quality on non-retina display looks bad then set
+  # `use_thin_strokes` to `true` and enable font smoothing by running the
+  # following command:
+  #   `defaults write -g CGFontRenderingFontSmoothingDisabled -bool NO`
+  #
+  # This is a global setting and will require a log out or restart to take
+  # effect.
   use_thin_strokes: true
 
 # Display the time it takes to redraw each frame.