`getValue` -> `value`
`getValueOr` -> `value_or`
`hasValue` -> `has_value`
`map` -> `transform`
The old API will be deprecated in the rebranch.
To avoid merge conflicts, use the new API already in the main branch.
rdar://102362022
Without this, we only considered a protocol refinement rule redundant if
it was derived by directly-stated protocol refinements. But this broke
when completion introduced a 'transitive' refinement [P].[R] => [P]
from two directly-stated refinements [P].[Q] => [P] and [Q].[R] => [Q].
Fixes rdar://problem/90402503.
