languages/rust: add rustaceanvim dependency rustfmt

See https://github.com/NotAShelf/nvf/pull/914 for more details.

docs/release-notes/rl-0.8.md

@@ -363,6 +363,7 @@
 - Add the `vim.languages.dart.flutter-tools.flutterPackage` option.
 - Fix the type of the `highlight` color options.
 - Add [vim-sleuth] plugin under `vim.utility.sleuth`.
+- Add missing `rustaceanvim` dependency `rustfmt`.
 
 [howird](https://github.com/howird):
 

modules/plugins/languages/rust.nix

@@ -140,7 +140,7 @@ in {
     (mkIf (cfg.lsp.enable || cfg.dap.enable) {
       vim = {
         startPlugins = ["rustaceanvim"];
-
+        extraPackages = [pkgs.rustfmt];
         pluginRC.rustaceanvim = entryAfter ["lsp-setup"] ''
           vim.g.rustaceanvim = {
           ${optionalString cfg.lsp.enable ''