Fix template type diffing coloring (r159216) when forcing color output to a file (not a terminal)

Reviewed (over the shoulder) by Richard Trieu.

llvm-svn: 159381
diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index 8b7332d..bd766d3 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -720,8 +720,11 @@
 
   if (Columns)
     printWordWrapped(OS, Message, Columns, CurrentColumn);
-  else
-    OS << Message;
+  else {
+    bool Normal = true;
+    applyTemplateHighlighting(OS, Message, Normal);
+    assert(Normal && "Formatting should have returned to normal");
+  }
 
   if (ShowColors)
     OS.resetColor();