title: toctree nested drop down
body: <p>I have a toctree in my index.rst that looks something like this:</p>
  
  <pre><code>.. toctree::
     :maxdepth: 2
  
     cat
     dog
     moose
  </code></pre>
  
  <p>I am looking to to nest the contents of my toctree similar to how it is done <a href="http://pexpect.readthedocs.io/en/stable/api/index.html" rel="noreferrer">here</a> with 'api documentation':</p>
  
  <p><a href="https://i.stack.imgur.com/epUEi.png" rel="noreferrer"><img src="https://i.stack.imgur.com/epUEi.png" alt="enter image description here"></a></p>
  
  <p>So ultimately make something like:</p>
  
  <pre><code>.. toctree::
     :maxdepth: 2
     :dropdown Animals
       cat
       dog
       moose
  </code></pre>
  
  <p>But I cannot seem to find anything that does this in the docs.</p>