title: How to arc patch a preview diff
body: <p>I created a diff (rather than revision) using <code>arc diff --preview</code> on one machine and I'd like to patch it on another machine. What command do I use? If I try <code>arc patch &lt;ID&gt;</code> I get:</p>
  
  <pre><code>Exception
  The diff or revision you specified is either invalid or you don't have
  permission to view it.
  </code></pre>