Range constructor about jsoncpp

[BillyDonahue]

This would need to be very carefully done, and gated on C++23 support.

I am also not sure that we would always want it to produce an arrayValue in a range constructor.
I also don't want to accept arbitrary constructor arguments assuming they're a range pair of iterators.

I've never used std::ranges before, but I believe ranges::to can be given arguments to help select the Value constructor, like:

template <ValueType vt>
using ValueTypeTag = std::integral_constant<ValueType, vt>;

template<typename R, ValueType vt>
Json::Value(std::ranges::from_range_t, R&& r, ValueTypeTag<vt>) : Value{vt} {
    std::ranges::for_each(std::forward<R>(r), [&](auto&& x) { append(x); });
}

// ...

vector<MyMessageClass> messages = TODO()
Json::Value json = messages
                      | std::ranges::views::transform(&MyMessageClass::toJson)
                      | std::ranges::to<Json::Value>(Json::ValueTypeTag<Json::arrayValue>{});

I think you can also maybe create nonmember function to do the same thing and provide it as an argument to std::ranges::to to produce Json::Value in this way. That is, I think there's a way to get the elegant range construction you want without modifying jsoncpp at all. But I don't know this for sure.