title: Changing the formatter of Icon/Button Columns
body: <p>Regarding this example here <a href="http://tabulator.info/docs/5.0/format#icon" rel="nofollow noreferrer">http://tabulator.info/docs/5.0/format#icon</a></p>
  <p>In the <code>cellClick</code> function, how can you change the icon used in the formatter?</p>
  <p>The use-case is simply changing a folder icon to folder-open when a cell is clicked.</p>