swift234

Rename "AccessKind" to "AccessSemantics".  NFC.

There are a lot of different ways to interpret the
"kind" of an access.  This enum specifically dictates
the semantic rules for an access:  direct-to-storage
and direct-to-accessor accesses may be semantically
different from ordinary accesses, e.g. if there are
observers or overrides.

Swift SVN r22290