Basic/Diagnostic: Kill off a few unnecessary functions now that refactoring is done, and add a note that the new setDiagnosticGroup{...} methods only operate on the current diagnostic state.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140771 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Diagnostic.cpp b/lib/Basic/Diagnostic.cpp
index 5b81458..cfe617e 100644
--- a/lib/Basic/Diagnostic.cpp
+++ b/lib/Basic/Diagnostic.cpp
@@ -172,7 +172,7 @@
   bool isPragma = L.isValid();
   FullSourceLoc Loc(L, *SourceMgr);
   FullSourceLoc LastStateChangePos = DiagStatePoints.back().Loc;
-  DiagnosticMappingInfo MappingInfo = DiagnosticMappingInfo::MakeInfo(
+  DiagnosticMappingInfo MappingInfo = DiagnosticMappingInfo::Make(
     Map, /*IsUser=*/true, isPragma);
 
   // Common case; setting all the diagnostics of a group in one place.