fix: apply final before the class keyword, obey the suppressions

[sawilde]

A couple of issues relating to ClassMustBeFinal

1. Address the incorrect placement of the final keyword - ClassMustBeFinal alter leading to syntax error #11538, ClassMustBeFinal tries to insert final into strange places. #11460
2. Respect suppression when using the --alter switch - --alter not respecting configuration suppression #11412

I couldn't find any tests that would break when I altered the code, so any advice on where to put tests to help evaluate this fix would be appreciated