fix(sway): use wayland WINIT backend in session env

WINIT_UNIX_BACKEND was set to x11, forcing winit apps onto XWayland in a
Wayland session, contradicting the rest of the block. Set it to wayland,
normalise the heredoc indentation, and drop the unused `options` arg.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyrathorpe/swaywm.nix

@@ -1,7 +1,6 @@
 {
   config,
   lib,
-  options,
   pkgs,
   ...
 }:
@@ -27,7 +26,7 @@ in
         export _JAVA_AWT_WM_NONREPARENTING=1
         # Misc
         export CLUTTER_BACKEND=wayland
-                export WINIT_UNIX_BACKEND=x11
+        export WINIT_UNIX_BACKEND=wayland
         export MOZ_ENABLE_WAYLAND=1
       '';
       # Core Wayland utilities. The lock screen, idle daemon, status bar and