title: asset() function in twig gives an NotFoundHttpException "No route found for "GET /favicon.ico"
body: <p>I have just installed a new Symfony project (I use <code>xampp</code>). When I started the application the favicon on the url tab wasn't showing, i opened the source code and opend the icon from there, but I got the error message I writed in the title.
  In the code the link is presented as: </p>
  
  <pre><code>&lt;link rel="icon" type="image/x-icon" href="{{ asset('favicon.ico') }}" /&gt;
  </code></pre>
  
  <p>and in the source code it was like </p>
  
  <pre><code> &lt;link rel="icon" type="image/x-icon" href="/favicon.ico" /&gt;
  </code></pre>
  
  <p>What is the problem, am I missing something ? 
  Thanks </p>