Merge pull request #9853 from nathawes/rdar32148117-multiline-string-highlighting-issues

[SyntaxColor] Improve highligting of multiline strings

include/swift/IDE/Formatting.h

@@ -81,6 +81,11 @@ public:
     else if (Line >= StartLine + Length) {
       Length = Line - StartLine + 1;
     }
+    else if (Line < StartLine) {
+      unsigned Delta = StartLine - Line;
+      StartLine -= Delta;
+      Length += Delta;
+    }
   }
 
 };