lib/plugins: take ownership of modules utils

These util functions were previously defined in `modules`, but
`plugins.utils` is a better home.

lib/modules.nix

@@ -10,6 +10,9 @@ let
     # Removed 2024-09-27
     specialArgs = "It has been integrated into `evalNixvim`";
     specialArgsWith = "It has been integrated into `evalNixvim`";
+    # Removed 2024-12-18
+    applyExtraConfig = "It has been moved to `lib.plugins.utils`";
+    mkConfigAt = "It has been moved to `lib.plugins.utils`";
   };
 in
 {
@@ -45,37 +48,6 @@ in
         helpers = self;
       } // extraSpecialArgs;
     };
-
-  /**
-    Apply an `extraConfig` definition, which should produce a `config` definition.
-    As used by `mkVimPlugin` and `mkNeovimPlugin`.
-
-    The result will be wrapped using a `mkIf` definition.
-  */
-  applyExtraConfig =
-    {
-      extraConfig,
-      cfg,
-      opts,
-      enabled ? cfg.enable or (throw "`enabled` argument not provided and no `cfg.enable` option found."),
-    }:
-    let
-      maybeApply = x: maybeFn: if builtins.isFunction maybeFn then maybeFn x else maybeFn;
-    in
-    lib.pipe extraConfig [
-      (maybeApply cfg)
-      (maybeApply opts)
-      (lib.mkIf enabled)
-    ];
-
-  mkConfigAt =
-    loc: def:
-    let
-      isOrder = loc._type or null == "order";
-      withOrder = if isOrder then lib.modules.mkOrder loc.priority else lib.id;
-      loc' = lib.toList (if isOrder then loc.content else loc);
-    in
-    lib.setAttrByPath loc' (withOrder def);
 }
 // lib.mapAttrs (
   name: msg: