Change default Windows shell to PowerShell

Update the Windows shell settings and comments so they look familiar to
Windows users, but comment out the shell settings for consistency with
Linux and Mac.

Stop checking COMSPEC when the configuration file does not specify which
shell to use, and just default to PowerShell.

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Windows configuration location has been moved from %USERPROFILE%\alacritty.yml
     to %APPDATA%\alacritty\alacritty.yml
+- Windows default shell is now PowerShell instead of cmd
 
 ### Fixed
 

alacritty_windows.yml

@@ -276,12 +276,11 @@ live_config_reload: true
 
 # Shell
 #
-# You can set `shell.program` to the path of your favorite shell, e.g. `/bin/fish`.
+# You can set `shell.program` to the path of your favorite shell, e.g. `cmd`.
 # Entries in `shell.args` are passed unmodified as arguments to the shell.
-shell:
+#shell:
-  program: cmd
+#  program: powershell
-  #args:
+#  args: []
-  #  - --login
 
 # Windows 10 ConPTY backend
 #

src/tty/windows/conpty.rs

@@ -14,7 +14,6 @@
 
 use super::{process_should_exit, Pty, HANDLE};
 
-use std::env;
 use std::i16;
 use std::mem;
 use std::os::windows::io::IntoRawHandle;
@@ -212,7 +211,7 @@ pub fn new<'a>(
     }
 
     // Get process commandline
-    let default_shell = &Shell::new(env::var("COMSPEC").unwrap_or_else(|_| "cmd".into()));
+    let default_shell = &Shell::new("powershell");
     let shell = config.shell().unwrap_or(default_shell);
     let initial_command = options.command().unwrap_or(shell);
     let mut cmdline = initial_command.args().to_vec();

src/tty/windows/winpty.rs

@@ -18,7 +18,6 @@ use std::io;
 use std::fs::OpenOptions;
 use std::os::windows::io::{FromRawHandle, IntoRawHandle};
 use std::os::windows::fs::OpenOptionsExt;
-use std::env;
 use std::sync::Arc;
 use std::u16;
 
@@ -96,7 +95,7 @@ pub fn new<'a>(
     let (conin, conout) = (winpty.conin_name(), winpty.conout_name());
 
     // Get process commandline
-    let default_shell = &Shell::new(env::var("COMSPEC").unwrap_or_else(|_| "cmd".into()));
+    let default_shell = &Shell::new("powershell");
     let shell = config.shell().unwrap_or(default_shell);
     let initial_command = options.command().unwrap_or(shell);
     let mut cmdline = initial_command.args().to_vec();