New rule `del-attr-with-constant`

[janosh]

Summary

new sibling for B009 (get-attr-with-constant):

# bad
delattr(cls, "_repr_mimebundle_")

# good
del cls._repr_mimebundle_

[fennr]

@MichaReiser can you assign issue to me?

[MichaReiser]

It could make sense to open a request for this rule upstream before adding it to Ruff, to avoid re-coding in the future (We can't add it to the bugbear category)