title: How to simply checkout branch by owner:branch
body: <p>On github, I'm looking for a straight forward way how to checkout a branch from a pull request.</p>
  
  <p>I can see a highlighted branch like <code>owner:branch</code>. </p>
  
  <p>The <code>owner</code> leads to a fork of a repository. The <code>branch</code> is a branch in the forked repo.</p>
  
  <p>Can I use this <code>owner:branch</code> to just copy it and paste in 1 line command?</p>