flake: filter out non-neovim files

flake.nix

@@ -22,24 +22,30 @@
       inherit (inputs.nixpkgs) lib;
       pkgs = inputs.nixpkgs.legacyPackages.${system};
       treefmtEval = inputs.treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
-      runtimeDeps = with pkgs; [
-        # mason / tree-sitter
-        gcc
-        cargo
-        nodejs
-
-        # telescope
-        ripgrep
-        fd
-      ];
     in {
       ### nix {run,shell,build}
-      packages.default =
+      packages.default = let
+        runtimeDeps = with pkgs; [
+          # mason / tree-sitter
+          gcc
+          cargo
+          nodejs
+
+          # telescope
+          ripgrep
+          fd
+        ];
+
+        src = lib.fileset.toSource {
+          fileset = lib.fileset.fileFilter (file: file.hasExt "lua") ./.;
+          root = ./.;
+        };
+      in
         pkgs.wrapNeovimUnstable pkgs.neovim-unwrapped
         (pkgs.neovimUtils.makeNeovimConfig {
             customRC = ''
-              set runtimepath^=${./.}
-              source ${./.}/init.lua
+              set runtimepath^=${src}
+              source ${src}/init.lua
             '';
           }
           // {wrapperArgs = ["--prefix" "PATH" ":" "${lib.makeBinPath runtimeDeps}"];});