title: Merge only one changeset from another branch
body: <p>I'm new to mercurial and I read that it's not possible to merge only a separate changeset from another branch.
  Then I don't know what's the best approach to solve that:</p>
  
  <ol>
  <li>I start with an stable revision R1</li>
  <li>I continue developing on R1: CS1,CS2,CS3</li>
  <li>At some point I need to solve bug from my stable revision R1. And I want to apply only one changeset from developing line (fe CS2)</li>
  </ol>
  
  <p>What's the best aproach?  As merging didn't work what I've done is make a patch of CS2 and then apply the patch in the new stable branch to fix the bug. That's the Mercurial way?</p>
  
  <p>Cheers,</p>