Fixed #31069, Refs #26431 -- Doc'd RegexPattern behavior change in passing optional named groups in Django 3.0.

[hramezani]

Ticket 31069

[felixxm]

@hramezani Thanks for this patch 👍 I left wording suggestions, please add also release notes under Backwards incompatible changes in 3.0 -> Miscellaneous.

[hramezani]

@felixxm Thanks for your review and suggestion.
what do you think about the following release note for Backwards incompatible changes:

*‌ The keyword arguments with ``None`` values in matched URL pattern are no
  longer get passed to view, also for not provided named parts.

[felixxm]

We can take a releases/3.0.1.txt as a pattern 🤔 , e.g.:

* ``RegexPattern``, used by :func:`~django.urls.re_path`, no longer return a
  keyword argument with ``None`` value to be passed to the view for the
  optional named group that is missing.

[hramezani]

• RegexPattern, used by :func:~django.urls.re_path, no longer return a
  keyword argument with None value to be passed to the view for the
  optional named group that is missing.

Thanks, I just replaced no longer return with no longer returns.

[felixxm]

@hramezani Thanks 👍