title: VSCode snippet transform to determine the containing directory
body: <p>I've been unable to determine the transform to use to grab the directory that a new file is in from the <code>TM_DIRECTORY</code> that VSCode exposes? </p>
  
  <p>i.e. For a path like <code>c:\a\b\c\d\e</code> I would like to get <code>e</code> as the output. I also have linux co-works so it should also work for something like <code>/mnt/a/b/c/d/e</code></p>