Displays content in a modal dialog.
\Symfony\Component\HttpFoundation\RequestRequest $request: The request object.
callable $_content: The body content callable that contains the body region of this page.
\Drupal\Core\Ajax\AjaxResponse AjaxResponse to return the content wrapper in a modal dialog.
public function modal(Request $request, $_content) {
return $this
->dialog($request, $_content, TRUE);
}