Update docs/tracker_stores.rst
Update docs/tracker_stores.rst

Co-Authored-By: mark922 <0be30a84cd9da611b526a3ec6e794d07ca9e3f94@gmail.com>
RasaHQ/rasa_core,RasaHQ/rasa_nlu,RasaHQ/rasa_core,RasaHQ/rasa_nlu,RasaHQ/rasa_nlu,RasaHQ/rasa_core