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

Source/core/inspector/InspectorInspectorAgent.cpp

Index: Source/core/inspector/InspectorInspectorAgent.cpp
diff --git a/Source/core/inspector/InspectorInspectorAgent.cpp b/Source/core/inspector/InspectorInspectorAgent.cpp
index 1c51a3b650ce2850c956abc635e0dc355d0fa324..852c08b50ca39ad2850eef09bdc59ffe75968cdc 100644
--- a/Source/core/inspector/InspectorInspectorAgent.cpp
+++ b/Source/core/inspector/InspectorInspectorAgent.cpp
@@ -87,9 +87,9 @@ void InspectorInspectorAgent::didClearDocumentOfWindowObject(LocalFrame* frame)
     int injectedScriptId = m_injectedScriptManager->injectedScriptIdFor(ScriptState::forMainWorld(frame));
     StringBuilder scriptSource;
     scriptSource.append(script);
-    scriptSource.append("(");
+    scriptSource.append('(');
     scriptSource.appendNumber(injectedScriptId);
-    scriptSource.append(")");
+    scriptSource.append(')');
     frame->script().executeScriptInMainWorld(scriptSource.toString());
 }