adding in endpoints parameter for the jupyter.chat method

[mcminis1]

Proposed changes:

• adding in kwarg for passing endpoints when calling chat in the jupyter notebook. Proposed change in Add endpoint functionality for chat method in rasa.jupyter #6051

Status (please check what you already did):

• updated the documentation
• updated the changelog (please check changelog for instructions)
• reformat files using black (please check Readme for instructions)

[mcminis1]

No tests exist (that I can find) for the jupyter notebook methods. So, I don't have any tests to extend. This change is trivial. It seems reasonable to me not to require an additional test.

[sara-tagger]

Thanks for submitting a pull request 🚀 @rgstephens will take a look at it as soon as possible ✨

[mcminis1]

@rgstephens I've also cleaned up some sphinx warnings for creating docs in the "Continuous Integration / Code Quality (pull_request)" test.

Let me know if you need something else to merge this PR. Thanks you!

[mcminis1]

@rgstephens Is this ready to Merge?