back out bogus `Ok`-wrapping suggestion on `?` arm type mismatch

back out bogus `Ok`-wrapping suggestion on `?` arm type mismatch

This suggestion was introduced in #51938 / 6cc78bf8d7 (while
introducing different language for type errors coming from `?` rather
than a `match`), but it has a lot of false-positives (as repeatedly
reported in Issues #52537, #52598, #54578, #55336), and incorrect
suggestions carry more badness than marginal good suggestions do
goodness. Just get rid of it (unless and until someone figures out how
to do it correctly).

Resolves #52537, resolves #54578.