swift234

Improve clarity/consistency of deinit diagnostics

The old message, "deinitializer does not have a parameter clause," was
confusing because it would be issued for a deinit that clearly *had* a
parameter clause.  Also, one out of three messages called deinitializers
"'deinitializer' functions."  Since "deinitializer" does not appear in
the program text, it doesn't make sense to quote it, either.

Swift SVN r21468