LibGUI: Syntax highlight string escape sequences

Author: https://github.com/oriko1010
Commit: d58cf1a05d
Pull-request: https://github.com/SerenityOS/serenity/pull/1411

Libraries/LibGUI/CppSyntaxHighlighter.cpp

@@ -23,6 +23,8 @@ static TextStyle style_for_token_type(CppToken::Type type)
     case CppToken::Type::SingleQuotedString:
     case CppToken::Type::Number:
         return { Color::from_rgb(0x800000) };
+    case CppToken::Type::EscapeSequence:
+        return { Color::from_rgb(0x800080), &Gfx::Font::default_bold_fixed_width_font() };
     case CppToken::Type::PreprocessorStatement:
         return { Color::from_rgb(0x008080) };
     case CppToken::Type::Comment: