fix(docs): rst syntax fix (#1090)

* With Sphinx, the title underlines need to be at least as long as the title

* match heading lengths

Author: MaxBittker

docs/integrations/react.rst

@@ -76,15 +76,15 @@ This will result in errors being reported twice to Sentry with the above setup,
 Read more about error boundaries `in this blog post <https://blog.sentry.io/2017/09/28/react-16-error-boundaries>`_.
 
 Redux
-----------------
+-----
 If you use `Redux <https://github.com/reactjs/redux>`_ there are some useful community maintained middleware packages 
 for annotating error reports with useful information, such as store state and recent actions:
 
 - `captbaritone/raven-for-redux <https://github.com/captbaritone/raven-for-redux>`_
 - `ngokevin/redux-raven-middleware <https://github.com/ngokevin/redux-raven-middleware>`_
 
 Redux Sagas Middleware
-----------------
+----------------------
 If you're using `Redux Saga <https://github.com/redux-saga/redux-saga>`_ be
 aware that it does not bubble errors up to the browsers uncaught exception handler.