swift

643197d2 - [sema] Fix availability narrowing fixits for macOS >= 11

[sema] Fix availability narrowing fixits for macOS >= 11 For macOS >= 11 the fixit for narrowing an availability check rather than adding a new one should fire if the major version is the same, like on other platforms. (cherry picked from commit c957826c286a5db3fe127eb6aa068371f38896cd)