flake: fix the check (#61)

The flake is missing nixvimLib, and the [simple template][tmpl] upstream
has changed since this repository was created. Align it with upstream to
fix the nix flake issue.

(cherry picked from commit 97facc071fd3408809bf74d32926ac9f14b550b7)

Co-authored-by: Roel de Cort <63876068+dc-tec@users.noreply.github.com>

flake.nix

@@ -28,27 +28,28 @@
         "x86_64-darwin"
       ];
 
-      perSystem =
-        {
+      perSystem = {
         system,
         pkgs,
         self',
         lib,
         ...
-        }:
-        let
+      }: let
+        nixvimLib = nixvim.lib.${system};
         nixvim' = nixvim.legacyPackages.${system};
-          nvim = nixvim'.makeNixvimWithModule {
+        nixvimModule = {
           inherit pkgs;
-            module = ./config;
+          module = import ./config; # import the module directly
+          # You can use `extraSpecialArgs` to pass additional arguments to your module files
+          extraSpecialArgs = {
+            # inherit (inputs) foo;
           };
+        };
+        nvim = nixvim'.makeNixvimWithModule nixvimModule;
       in
       {
         checks = {
-            default = pkgs.nixvimLib.check.mkTestDerivationFromNvim {
-              inherit nvim;
-              name = "A nixvim configuration";
-            };
+          default = nixvimLib.check.mkTestDerivationFromNixvimModule nixvimModule;
           pre-commit-check = pre-commit-hooks.lib.${system}.run {
             src = ./.;
             hooks = {
@@ -56,7 +57,6 @@
               nixfmt-rfc-style.enable = true;
             };
           };
-          };
 
           formatter = pkgs.nixfmt-rfc-style;