wrapper/rc: ignore user directories by default

modules/wrapper/rc/options.nix

@@ -24,6 +24,26 @@ in {
       take a look at the [{option}`official documentation`](https://neovim.io/doc/user/lua.html#vim.loader.enable()).
     '';
 
+    disableDefaultRuntimePaths = mkOption {
+      type = bool;
+      default = true;
+      example = false;
+      description = ''
+        Disables the default runtime paths that are set by Neovim
+        when it starts up. This is useful when you want to have
+        full control over the runtime paths that are set by Neovim.
+
+        ::: {.note}
+        To avoid leaking imperative user configuration into your
+        configuration, this is enabled by default. If you wish
+        to load configuration from user configuration directories
+        (e.g. `$HOME/.config/nvim`, `$HOME/.config/nvim/after`
+        and `$HOME/.local/share/nvim/site`) you may set this
+        option to true.
+        :::
+      '';
+    };
+
     additionalRuntimePaths = mkOption {
       type = listOf (either path str);
       default = [];
@@ -90,6 +110,15 @@ in {
           end
         ''}
 
+        ${optionalString cfg.disableDefaultRuntimePaths ''
+          -- Remove default user runtime paths from the
+          -- `runtimepath` option to avoid leaking user configuration
+          -- into the final neovim wrapper
+          vim.opt.runtimepath:remove(vim.fn.stdpath('config'))              -- $HOME/.config/nvim
+          vim.opt.runtimepath:remove(vim.fn.stdpath('config') .. "/after")  -- $HOME/.config/nvim/after
+          vim.opt.runtimepath:remove(vim.fn.stdpath('data') .. "/site")     -- $HOME/.local/share/nvim/site
+        ''}
+
         ${optionalString cfg.enableLuaLoader "vim.loader.enable()"}
       '';