title: Limit subject line of git commit message to 50 characters
body: <p>I often use <code>vim</code> to format my git commit messages.  A trend that I am seeing with <a href="https://chris.beams.io/posts/git-commit/#limit-50" rel="nofollow noreferrer">increasing</a> <a href="https://udacity.github.io/git-styleguide/" rel="nofollow noreferrer">popularity</a> is that the first line of the commit message should be limited to 50 characters and then subsequent lines should be limited to 72 characters.</p>
  
  <p><a href="https://stackoverflow.com/questions/11023194/automatically-wrap-long-git-commit-messages-in-vim">I already know how to make my commit wrap at 72 characters based on my <code>vimrc</code> file</a>:</p>
  
  <pre><code>syntax on
  au FileType gitcommit set tw=72
  </code></pre>
  
  <p>Is there a way to make <code>vim</code> autowrap the first line at 50 characters and then 72 characters after that?</p>
  
  <p>An equally good answer could highlight everything after the 50th column on <strong>only</strong> the first line to indicate that my header is too long ...</p>