X.A.WithAll: Add killOthers

This adds the function `killOthers`, which kills all unfocused windows
on the current workspace.

As discussed in the PR itself [1], the module suffix `WithAll` is not
quite optimal at this point, as we are acting on window _groups_ and not
necessarily just all window on a workspace.  However, in order to keep
this commit atomic, this consideration is postponed until another day.

[1]: https://github.com/xmonad/xmonad-contrib/pull/602

CHANGES.md

@@ -302,6 +302,11 @@
 
   * Add support for GHC 9.0.1.
 
+  * `XMonad.Actions.WithAll`
+
+    - Added `killOthers`, which kills all unfocused windows on the
+      current workspace.
+
   * `XMonad.Prompt.XMonad`
 
     - Added `xmonadPromptCT`, which allows you to create an XMonad

XMonad/Actions/WithAll.hs

@@ -5,15 +5,16 @@
 -- Stability    : unstable
 -- Portability  : unportable
 --
--- Provides functions for performing a given action on all windows of
--- the current workspace.
+-- Provides functions for performing a given action on all or certain
+-- groups of windows on the current workspace.
 -----------------------------------------------------------------------------
 
 module XMonad.Actions.WithAll (
     -- * Usage
     -- $usage
     sinkAll, withAll,
-    withAll', killAll) where
+    withAll', killAll,
+    killOthers) where
 
 import XMonad.Prelude hiding (foldr)
 
@@ -50,3 +51,7 @@ withAll f = withWindowSet $ \ws -> let all' = integrate' . stack . workspace . c
 -- | Kill all the windows on the current workspace.
 killAll :: X()
 killAll = withAll killWindow
+
+-- | Kill all the unfocused windows on the current workspace.
+killOthers :: X ()
+killOthers = withUnfocused killWindow

XMonad/Doc/Extending.hs

@@ -336,8 +336,8 @@ edit your key bindings.
     Experimental rewrite of "XMonad.Layout.WindowNavigation".
 
 * "XMonad.Actions.WithAll":
-    Provides functions for performing a given action on all windows of
-    the current workspace.
+    Provides functions for performing a given action on all or certain
+    groups of windows on the current workspace.
 
 * "XMonad.Actions.Workscreen":
     A workscreen permits to display a set of workspaces on several screens. In