Keep the wallpaper when movie restores the screen layout

.fehbg now saves its random picks to ~/.cache/wallpapers and redraws them with
--keep; screen-layout passes this through with --keep-wallpaper, used by movie.

.local/bin/screen-layout

@@ -1,6 +1,7 @@
 #!/bin/bash
 # Sets up the outputs, wallpaper and trayer for whatever monitors are connected.
 # Called by xmonad at startup and on monitor (dis)connect, and by `movie` on exit.
+# --keep-wallpaper redraws the current wallpaper instead of picking new random ones.
 
 if xrandr --query | grep -q '^HDMI-1-0 connected'; then
     xrandr --output HDMI-1-0 --preferred --primary --output eDP-1 --right-of HDMI-1-0 --preferred
@@ -10,7 +11,11 @@ else
     tray=0
 fi
 
-~/.fehbg
+if [[ $1 == --keep-wallpaper ]]; then
+    ~/.fehbg --keep
+else
+    ~/.fehbg
+fi
 
 # Replace any running trayer, so there's never more than one
 pkill -x trayer