Attach any tag type's documentation to its typedef if
latter does not have one of its own. // rdar://13067629


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173586 91177308-0d34-0410-b5e6-96231b3b80d8
Fix comment.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173587 91177308-0d34-0410-b5e6-96231b3b80d8