title: Python click, Can you make -h as an alias
body: <p>I have recently found the click library (<a href="http://click.pocoo.org/6/" rel="noreferrer">http://click.pocoo.org/6/</a>) and I love it. </p>
  
  <p>I am trying to figure out if it is possible to create an alias for the <code>--help</code> option which shortcuts to the help. So, for example:</p>
  
  <pre><code>app.py --help
  </code></pre>
  
  <p>gives the help for the main app and </p>
  
  <pre><code>app.py sub --help
  </code></pre>
  
  <p>will give the help for the sub. I want to be able to use -h as well. If I were creating the option, it may look something like:</p>
  
  <pre><code>@click.option('-h', '--help')
  </code></pre>
  
  <p>but the <code>--help</code> option is built in. Is there a way to extend that option or create an alias for it?</p>