LibJS+LibGUI+js: Handle UnterminatedRegexLiteral in syntax highlighters

Author: https://github.com/linusg
Commit: 7d83665635
Pull-request: https://github.com/SerenityOS/serenity/pull/3601

Userland/js.cpp

@@ -616,6 +616,7 @@ int main(int argc, char** argv)
                 case JS::TokenType::RegexLiteral:
                 case JS::TokenType::RegexFlags:
                 case JS::TokenType::UnterminatedStringLiteral:
+                case JS::TokenType::UnterminatedRegexLiteral:
                     stylize({ start, end }, { Line::Style::Foreground(Line::Style::XtermColor::Green), Line::Style::Bold });
                     break;
                 case JS::TokenType::BracketClose: