Use StringBuilder::appendLiteral() / StringBuilder::append(char) when possible

Source/core/inspector/InspectorOverlay.cpp

Index: Source/core/inspector/InspectorOverlay.cpp
diff --git a/Source/core/inspector/InspectorOverlay.cpp b/Source/core/inspector/InspectorOverlay.cpp
index 172fcba568342b9cede541d1d9384e7a0137ac3d..5492252f41d193a4d6013440f386a5a5554920e4 100644
--- a/Source/core/inspector/InspectorOverlay.cpp
+++ b/Source/core/inspector/InspectorOverlay.cpp
@@ -636,9 +636,9 @@ PassRefPtr<JSONObject> buildElementInfo(Element* element)
     }
     if (pseudoElement) {
         if (pseudoElement->pseudoId() == BEFORE)
-            classNames.append("::before");
+            classNames.appendLiteral("::before");
         else if (pseudoElement->pseudoId() == AFTER)
-            classNames.append("::after");
+            classNames.appendLiteral("::after");
     }
     if (!classNames.isEmpty())
         elementInfo->setString("className", classNames.toString());