chore: clean up swaylock-bg script

pkgs/swaylock-bg.nix

@@ -2,17 +2,10 @@ self:
 with self; ''
   # Dependencies:
   # swaylock
-
-  # Make sure we aren't running twice
-  RUNNING=$(${procps}/bin/pgrep -c ${swaylock}/bin/swaylock)
-  if [ "$RUNNING" -ne 0 ]; then
-    exit 0
-  fi
-
   IMAGE="$XDG_CONFIG_HOME/wallpaper.jpg"
   LOCKARGS=""
 
-  for OUTPUT in $(${sway}/bin/swaymsg -t get_outputs | ${jq}/bin/jq -r '.[].name')
+  for OUTPUT in $(${sway}/bin/swaymsg --type get_outputs | ${jq}/bin/jq --raw-output '.[].name')
   do
       LOCKARGS="''${LOCKARGS} --image ''${OUTPUT}:''${IMAGE}"
   done