title: CKEditor allow <span> inside <a> tag
body: <p>I want to add <code>&lt;span&gt;</code> tag inside of an <code>&lt;a&gt;</code> tag in the CKEditor source:</p>
  
  <pre><code>&lt;a href="http://google.com"&gt;&lt;span&gt;Link here&lt;/span&gt;&lt;/a&gt;
  </code></pre>
  
  <p>But when I add the HTML in CKEditor in source mode, it converts it to:</p>
  
  <pre><code>&lt;a href="http://google.com"&gt;Link Here&lt;/a&gt;
  </code></pre>
  
  <p>How can I allow HTML tags inside a <code>href</code>?</p>