Method on_arg_id

extlibs/fmt/include/fmt/format.h:2652–2655

  FMT_CONSTEXPR void on_text(const Char*, const Char*) {}

  FMT_CONSTEXPR void on_arg_id() {
    arg_id_ = context_.next_arg_id();
    check_arg_id();
  }
  FMT_CONSTEXPR void on_arg_id(int id) {
    arg_id_ = id;
    context_.check_arg_id(id);