- Allow named opaque types in typed patterns and subscripts
- Fix inheritance clause printing for `GenericParamList`
- clang-format changes from previous commit on this branch
Also, store the end location of the where clause explicitly, so that
we can recover it even if there are no requirements.
This fixes one of the failing tests when parser lookup is disabled in
swift-ide-test by ensuring that the source range of the function
extends to the end of the 'where' clause, even though the 'where'
clause has a code completion token in it.