Shorten DotDebugLocEntry to just DebugLocEntry and reformat.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204102 91177308-0d34-0410-b5e6-96231b3b80d8
Add explanatory comment.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204103 91177308-0d34-0410-b5e6-96231b3b80d8