Bug 1601634 - Improve the display of the Try documentation r=ahal

Differential Revision: https://phabricator.services.mozilla.com/D56042

--HG--
extra : moz-landing-system : lando

tools/tryselect/docs/index.rst

@@ -21,7 +21,8 @@ changeset gets marked 'public'. This ensures changes that are shared with others
 get mutated.  Pushing to try doesn't actually share the changeset with anyone, so changesets remain
 in the 'draft' state and they are still ok to mutate.
 
-.. rubric:: Using Try
+Using Try
+---------
 
 Before you can push to try, you'll need to have the proper credentials and do some light setup. See
 the :doc:`configuration` page for more information.
@@ -62,8 +63,10 @@ easy and doesn't require more actions from the developer.
 
 .. image:: img/add-new-jobs.png
 
+Table of Contents
+-----------------
+
 .. toctree::
-  :caption: Table of Contents
   :maxdepth: 2
 
   configuration
@@ -72,7 +75,8 @@ easy and doesn't require more actions from the developer.
   tasks
 
 
-.. rubric:: Indices and tables
+Indices and tables
+------------------
 
 * :ref:`genindex`
 * :ref:`modindex`