title: Show entire toctree in Read The Docs sidebar
body: <p>It's my understanding the new Read The Docs theme <a href="https://sphinx-rtd-theme.readthedocs.io/en/latest/configuring.html#how-the-table-of-contents-displays" rel="nofollow noreferrer">generates the sidebar from the toctree</a> with a depth of 2.  My documentation is relatively deep, and a depth of 2 is not enough for it to be useful.  How can I increase this limit, or preferably remove it entirely?</p>
  
  <p>If that's not reasonably possible, how can I use local ToC's instead of the global toctree?</p>