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

Source/core/inspector/ContentSearchUtils.cpp

Index: Source/core/inspector/ContentSearchUtils.cpp
diff --git a/Source/core/inspector/ContentSearchUtils.cpp b/Source/core/inspector/ContentSearchUtils.cpp
index fb0f626876cab3958fefd2217b607ee53d9e0e23..d84f74dd2472f5d59344727fc5483e9e34dd66db 100644
--- a/Source/core/inspector/ContentSearchUtils.cpp
+++ b/Source/core/inspector/ContentSearchUtils.cpp
@@ -49,7 +49,7 @@ static String createSearchRegexSource(const String& text)
 
     for (unsigned i = 0; i < text.length(); i++) {
         if (specials.find(text[i]) != kNotFound)
-            result.append("\\");
+            result.append('\\');
         result.append(text[i]);
     }