[PATCH] D31709: [NFC] Refactor DiagnosticRenderer to use FullSourceLoc

[Christof Douma via Phabricator via cfe-commits]

christof commandeered this revision.
christof added a reviewer: sanwou01.
christof added a comment.

This refactoring was ready to land some time ago, except for a few small details.  It's a shame if we don't commit this refactoring, so with @sanwou01 
his agreement, I'm taking over this patch.


https://reviews.llvm.org/D31709