Introduce code completion results for Objective-C methods, both when

Introduce code completion results for Objective-C methods, both when
declaring methods and when sending messages to them, by bringing all
of the selector into TypedCheck chunks in the completion result. This
way, we can improve the sorting of these results to account for the
full selector name rather than just the first chunk.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@116746 91177308-0d34-0410-b5e6-96231b3b80d8