title: symfony knp_snappy.pdf doesn't make link in a-tag
body: <p>This is my code:</p>
  
  <pre><code>$html = $this-&gt;renderView('@App/pdf/default.html.twig', [
      'item' =&gt; $item
  ]);
  return new PdfResponse(
      $this-&gt;get('knp_snappy.pdf')-&gt;getOutputFromHtml($html),
      StringManipulation::slugify($item-&gt;getName()) . '.pdf'
  );
  </code></pre>
  
  <p>That's show tag a in pdf-file like a text, not link. How can i make it as link?</p>