Neovim, remove default rust lint enforcement

I'm sorry to say but I use 2 spaces instead of 4, and I prefer a line
width of 80, not 100. For that reason I'm disabling rust linting if the
language is enabled.

hmModules/apps/neovim/app.nix

@@ -105,7 +105,13 @@
         ]);
 
         rust-pkg = lopts cfgl.rust.enable (with pkgs.vimPlugins; [
-          rustaceanvim
+          {
+            plugin = rustaceanvim;
+            type = "lua";
+            config = ''
+              vim.g.rust_recommended_style = 0
+            '';
+          }
         ]);
 
         go-pkg = lopts cfgl.go.enable (with pkgs.vimPlugins; [