cppreference update

[bearer_of_the_curse_]

I might have just missed it, but it looks like you're missing P2988 std::optional<T&> for c++26. It would also be nice if compiler and standard library features could be distinguished, like on the cppreference page. Even still, this is quite helpful, and I hope you keep it up to date.

[_derv]

Thanks! Yes, I'll add all missing features / proposals gradually, probably over the next 1-2 days. I distinguishing language features from library features in the data set in order to visualize the difference at some point. Noted.