flake: add nixvimModules flake-parts module

flake/flake-modules/default.nix

@@ -2,6 +2,7 @@
 let
   # Modules for the flakeModules output and the default module
   defaultModules = {
+    nixvimModules = ./nixvimModules.nix;
     nixvimConfigurations = ./nixvimConfigurations.nix;
   };
 

flake/flake-modules/nixvimModules.nix

@@ -0,0 +1,27 @@
+{
+  lib,
+  flake-parts-lib,
+  moduleLocation,
+  ...
+}:
+{
+  options = {
+    flake = flake-parts-lib.mkSubmoduleOptions {
+      nixvimModules = lib.mkOption {
+        type = with lib.types; lazyAttrsOf deferredModule;
+        default = { };
+        apply = lib.mapAttrs (
+          name: module: {
+            _file = "${toString moduleLocation}#nixvimModules.${name}";
+            imports = [ module ];
+          }
+        );
+        description = ''
+          Nixvim modules.
+
+          You may use this for reusable pieces of configuration, utility modules, etc.
+        '';
+      };
+    };
+  };
+}