Make `#![feature]` suggestion MaybeIncorrect
Fixes https://github.com/rust-lang/rust-clippy/issues/12784
The `unstable_name_collisions` lint uses `disabled_nightly_features` to mention the feature name, but accepting the suggestion would result in an ambiguity error
There are other calls where accepting the feature gate would fix code when ran with `cargo fix --broken-code`, though it's not always desirable to add a feature gate even if the user is currently on nightly so MaybeIncorrect seems appropriate
Matthias Krüger
779fe95298