title: Symfony 'trans' domain inside Twig template
body: <p>I'd like to do this:</p>
  
  <pre><code>$this-&gt;get('translator')-&gt;trans('notice.unregistered', array(), 'index');
  </code></pre>
  
  <p>Inside Twig template, so I don't have to pass this as an argument. How?</p>