finally use xserver.extraLayouts correctly

overlays/customscripts/src/x0

@@ -1,6 +1,6 @@
 #!/usr/bin/env nix-shell
 #! nix-shell -i bash -p curl
 for x in $@; do
-  curl -F file=@"$x" https://x0.at/
+  curl -F "file=@\"$x\"" https://x0.at/
   echo " "
 done