title: Is it possible to annotate "git diff"?
body: <p>I'm trying to summarize the difference between an "old" and "new" state of the codebase.</p>
  
  <ul>
  <li>I could just do "git log", but sadly the commit messages aren't always sufficient.</li>
  <li>I could do "git diff", but I'd like to see some explanations to the differences I'm seeing, or at least commit hashes to save for later</li>
  <li>I could do a "git diff --stat" and then "git annotate" for the files that changed, but I don't see how to ask annotate to only show changes since a particular commit.</li>
  </ul>
  
  <p>Ideally, I'd like to get the output of "git diff" where all the "+" and "-" lines would be annotated with information about commits which last introduced these changes; ideally, in a git pretty format (e.g. hash, author and date).</p>
  
  <p>How can this be achieved?</p>