Make `Minitest/AssertPredicate` aware of `assert_not_predicate`

[Earlopain]

Is your feature request related to a problem? Please describe.

Currently Minitest/AssertPredicate corrects assert(foo.bar?) to assert_predicate(foo, :bar?).
It would be nice if the same is also true for the negation of this. assert_not(foo.bar?) to assert_not_predicate(foo, :bar?).

I have openend this issue here instead of the minitest gem because assert_not_predicate and assert_not are rails specific methods.

[Earlopain]

@koic could you give me some pointers on how you would approach this? I'm not sure where I would start when implementing.

Would it make sense to:

• Make Minitest/AssertPredicate aware of this by default
• Add a config to Minitest/AssertPredicate that would be default enhanced here if the gem is present (are there other cops here that do this I could look take a look at?)
• Something else entirely?