neovimUtils.grammarToPlugin: install tree-sitter grammars for neovim without nvim-treesitter

nvim-treesitter installs tons of queries that are picked up
by neovim even though we sometimes dont want those queries.
This makes it possible to install grammars without nvim-treesitter which
becomes more and more a repository like nvim-lspconfig, aka a repo that
lists others.

pkgs/applications/editors/neovim/utils.nix

@@ -9,8 +9,11 @@
 , python3Packages
 , writeText
 , wrapNeovimUnstable
+, runCommand
 }:
 let
+  inherit (vimUtils) toVimPlugin;
+
    /* returns everything needed for the caller to wrap its own neovim:
    - the generated content of the future init.vim
    - the arguments to wrap neovim with
@@ -197,11 +200,38 @@ let
     inherit (vimUtils) toVimPlugin;
     inherit lua;
   };
+
+  grammarToPlugin = grammar:
+    let
+      name = lib.pipe grammar [
+        lib.getName
+
+        # added in buildGrammar
+        (lib.removeSuffix "-grammar")
+
+        # grammars from tree-sitter.builtGrammars
+        (lib.removePrefix "tree-sitter-")
+        (lib.replaceStrings [ "-" ] [ "_" ])
+      ];
+    in
+
+    toVimPlugin (runCommand "vimplugin-treesitter-grammar-${name}"
+      {
+        meta = {
+          platforms = lib.platforms.all;
+        } // grammar.meta;
+      }
+      ''
+        mkdir -p $out/parser
+        ln -s ${grammar}/parser $out/parser/${name}.so
+      '');
+
 in
 {
   inherit makeNeovimConfig;
   inherit generateProviderRc;
   inherit legacyWrapper;
+  inherit grammarToPlugin;
 
   inherit buildNeovimPlugin;
   buildNeovimPluginFrom2Nix = lib.warn "buildNeovimPluginFrom2Nix was renamed to buildNeovimPlugin" buildNeovimPlugin;

pkgs/applications/editors/vim/plugins/nvim-treesitter/overrides.nix

@@ -1,8 +1,9 @@
-{ lib, callPackage, tree-sitter, neovim, runCommand }:
+{ lib, callPackage, tree-sitter, neovim, neovimUtils, runCommand }:
 
 self: super:
 
 let
+  inherit (neovimUtils) grammarToPlugin;
   generatedGrammars = callPackage ./generated.nix {
     inherit (tree-sitter) buildGrammar;
   };
@@ -27,31 +28,6 @@ let
       })
     generatedDerivations;
 
-  grammarToPlugin = grammar:
-    let
-      name = lib.pipe grammar [
-        lib.getName
-
-        # added in buildGrammar
-        (lib.removeSuffix "-grammar")
-
-        # grammars from tree-sitter.builtGrammars
-        (lib.removePrefix "tree-sitter-")
-        (lib.replaceStrings [ "-" ] [ "_" ])
-      ];
-    in
-
-    runCommand "nvim-treesitter-grammar-${name}"
-      {
-        meta = {
-          platforms = lib.platforms.all;
-        } // grammar.meta;
-      }
-      ''
-        mkdir -p $out/parser
-        ln -s ${grammar}/parser $out/parser/${name}.so
-      '';
-
   allGrammars = lib.attrValues generatedDerivations;
 
   # Usage: