Key changes include:
- Removal of the word "syntax" from the lint message. More accurately,
it could have been something like "syntax group" or "syntax
category", but avoiding it completely is easier.
- The primary lint message now reflects exactly which mismatch is
occurring, instead of trying to be general. A new `help` line is
general across the mismatch kinds.
- Suggestions have been reduced to be more minimal, no longer also
changing non-idiomatic but unrelated aspects.
- Suggestion text no longer mentions changes when those changes don't
occur in that specific suggestion.
