title: Change the error message in inserting a url with $ form -> $ filed
body: <p>I want to change the error message that comes out when you enter a url wrong. I show you what I mean:</p>
  <p><a href="https://i.stack.imgur.com/ueirY.png" rel="nofollow noreferrer">Image</a></p>
  <p>The message must become: <strong>Inserisci un URL valido. Es: <a href="https://www.google.it" rel="nofollow noreferrer">https://www.google.it</a></strong></p>
  <p>I am modifying the view.php generated automatically by gii. Here is the code:</p>
  <p><code>&lt;?= $form-&gt;field($model, 'link')-&gt;input('url')?&gt;</code></p>
  <p>This is the function I use to enter a valid url.</p>