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.