title: Git: How to swap two files
body: <p>How can I swap two files, keeping them marked so in the history?
  (Except for doing it manually.)</p>
  
  <p>I'd expect some flag for <code>git mv</code>, like,</p>
  
  <pre><code>git mv --swap foo.txt bar.txt
  </code></pre>
  
  <p>which would produce</p>
  
  <pre><code># renamed:    foo.txt -&gt; bar.txt
  # renamed:    bar.txt -&gt; foo.txt
  </code></pre>
  
  <p>Is there support for this in git?</p>