Update comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202917 91177308-0d34-0410-b5e6-96231b3b80d8
Unindent namespace.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202918 91177308-0d34-0410-b5e6-96231b3b80d8
Expand slightly on comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202919 91177308-0d34-0410-b5e6-96231b3b80d8