Auto traits in `dyn Trait + Auto` are suggestable
Not sure why I had made the `IsSuggestableVisitor` have that rule to not consider `dyn Trait + Auto` to be suggestable.
It's possible that this was done because of the fact that we don't print the right parentheses for `&(dyn Trait + Auto)`, but that's a problem with printing these types in general that we probably have tracked somewhere else...
