Expand xdg config

Signed-off-by: Nikolaos Karaolidis <nick@karaolidis.com>

users/configs/kitty/default.nix

@@ -1,5 +1,8 @@
-{ user ? throw "user argument is required" }: { ... }:
+{ user ? throw "user argument is required" }: { config, ... }:
 
+let
+  hmConfig = config.home-manager.users."${user.name}";
+in
 {
   home-manager.users."${user.name}" = {
     programs.kitty = {
@@ -9,6 +12,6 @@
       '';
     };
 
-    home.persistence."/cache${user.home}".directories = [ ".cache/kitty" ];
+    home.persistence."/cache${user.home}".directories = [ "${hmConfig.xdg.relativeCacheHome}/kitty" ];
   };
 }