P2781 R9 std::constexpr_wrapper

[wg21bot]

P2781R9 std::constexpr_wrapper (Zach Laine, Matthias Kretz, Hana Dusíková)

[JeffGarland]

This is the post-Sofia entry for 1458

@tkoeppe can you confirm that R9 was applied?

[jwakely]

Yes it was. R9 was attached to the Sofia wiki straw polls page, and that version was applied. Presumably the bot opened this issue after #1458 got closed.

[jwakely]

See cplusplus/draft#8018