This allows building sourcekitd and swift-refactor with `SWIFT_BUILD_SWIFT_SYNTAX=NO`. In these builds, the `relatedidents` and `find-syntactic-rename-ranges` requests will always return an error.
I will remove the `syntactic-rename` refactoring action in a follow-up commit. Clients should always ask for rename ranges and perform the rename by themselves instead of asking for a renamed file.
This change makes us treat it exactly as we do 'init'. We don't allow renaming the base name,
and don't fail if the basename doesn't match for calls.
Also:
- explicit init calls/references like `MyType.init(42)` are now reported with
'init' as a keywordBase range, rather than nothing.
- cursor info no longer reports rename as available on init/callAsFunction
calls without arguments, as there's nothing to rename in that case.
- Improved detection of when a referenced function is a call (rather than
reference) across syntactic rename, cursor-info, and indexing.
Resolves rdar://problem/60340429
