LibJS: Add BigInt

Author: https://github.com/linusg
Commit: 0ff9d7e189
Pull-request: https://github.com/SerenityOS/serenity/pull/2509
Reviewed-by: https://github.com/alimpfard

Libraries/LibJS/MarkupGenerator.cpp

@@ -217,6 +217,7 @@ MarkupGenerator::StyleType MarkupGenerator::style_type_for_token(Token token)
     case TokenType::UnterminatedTemplateLiteral:
         return StyleType::Invalid;
     case TokenType::NumericLiteral:
+    case TokenType::BigIntLiteral:
         return StyleType::Number;
     case TokenType::StringLiteral:
     case TokenType::TemplateLiteralStart: