Add an autofix for E251

[Skylion007]

Almost all the trivial pycodestyle e autofixes https://docs.astral.sh/ruff/rules/#error-e are implemented, but there are few that are missing that seem quite trivial to implement. The first of which is E251. I first brought his up in #8312, and @charliermarsh mentioned it as fixed in #8623, but that does not seem to be case as indicated by the both rule webpage https://docs.astral.sh/ruff/rules/unexpected-spaces-around-keyword-parameter-equals/ , and trying to apply an autofix to the example in the documentation.

[charliermarsh]

Oh sorry, missed that one. I will add now.