title: Vim foldmethod=indent when indent is two spaces
body: <p>I have XML which looks like this:</p>
  
  <pre><code>&lt;object&gt;
    &lt;object&gt;
      a
    &lt;/object&gt;
    &lt;object&gt;
      b
    &lt;/object&gt;
  &lt;/object&gt;
  </code></pre>
  
  <p>and to edit it more easily, I would like to use folding, but when I try <code>set foldmethod=indent</code> it does nothing. Possible it have something to do with that my xml is indented with two spaces, not four, but I'm not sure about that. </p>
  
  <p>How to turn on indenting for such file properly? </p>