title: git log when HEAD is behind tip?
body: <p>Let's say that HEAD is at the final commit in master, and the log looks like this</p>
  
  <pre><code>$ git log --oneline
  bcaee1c 15 July update
  02ff17a add feature x
  0910b6f end of weekly update
  c2b7189 add 03 july update
  737be94 add feature y
  </code></pre>
  
  <p>Now I want to go look at the past:</p>
  
  <pre><code>$ git checkout 0910b6f
  </code></pre>
  
  <p>now the log shows no hint of the more recent state -- the relative future from HEAD</p>
  
  <pre><code>$ git log --oneline
  
  0910b6f end of weekly update
  c2b7189 add 03 july update
  737be94 add feature y
  </code></pre>
  
  <p>Ok, no problem, I just "remember" or "write down" that the furthest-ahead commit is <code>bcaee1c</code> and I can get back with a <code>git checkout bcaee1c</code>, but BAMMO, here comes a phone call, a bunch of emergency meetings, a forced reboot, a weekend, and I "forget" and / or lose the sticky note.  I come back (much) later with all that mental context blown and start creating away, only to discover later that I've messed up and have a forensics job with reset and revert and rewind.</p>
  
  <p>Can I get <code>git log</code> to show the future of <code>HEAD</code>?  Is there a better git-fu for this scenario?</p>