Change exit hyprland to SHIFT M

Too many times I pressed SUPER M by accident because I wanted to
press SUPER W to close something. So now closing hyprland is
SUPER SHIFT M instead.

hypr/keybindings.conf

@@ -1,7 +1,7 @@
 bind = $mainMod, T, exec, $terminal
 bind = $mainMod, B, exec, $browser
 bind = $mainMod, W, killactive,
-bind = $mainMod, M, exit,
+bind = $mainMod SHIFT, M, exit,
 bind = $mainMod, E, exec, $fileManager
 bind = $mainMod, V, togglefloating,
 bindr = $mainMod, SUPER_L, exec, $app_menu