Fix incorrect suggestion for trait bounds involving binary operators
This PR fixes#93927, #92347, #93744 by replacing the bespoke trait-suggestion logic in `op.rs` with a more common code path.
The downside is that this fix causes some suggestions to not include an `Output=` type, reducing their usefulness.
Note that this causes one case in the `missing-bounds.rs` test to fail rustfix. So I would need to move that code into a separate non-fix test if this PR is otherwise acceptable.
d6a57d3730