fix: aerc on darwin

switch to using xdg so config is saved in home dir
instead of ~/Library/Preferences/aerc/

modules/darwin/user.nix

@@ -10,11 +10,7 @@
     };
 
     # Used for aerc
-    home-manager.users.${config.user} = {
-      home.sessionVariables = {
-        XDG_CONFIG_HOME = "${config.homePath}/.config";
-      };
-    };
+    home-manager.users.${config.user}.xdg.enable = true;
 
   };