title: How to enable Mercurial extensions (such as mq)?
body: <p>I have installed Mercurial from the Ubuntu package repository. However I don't know how to enable extensions (<code>q*</code> commands). How should I do that? The help shows that </p>
  
  <pre><code>enabled extensions:
  style  (no help text available)
  </code></pre>
  
  <p>I want to enable mq and hgk.</p>