Method on_error

extlibs/fmt/include/fmt/core.h:605–607

  FMT_CONSTEXPR void check_arg_id(basic_string_view<Char>) {}

  FMT_CONSTEXPR void on_error(const char* message) {
    ErrorHandler::on_error(message);
  }

  FMT_CONSTEXPR ErrorHandler error_handler() const { return *this; }
};