ValueTask versions for `mapAsync` and `chooseAsync` and other async functions

[xperiandri]

It would be nice to have functions that accept functions returning ValueTask in addition to Task Maybe something like ValueTaskSeq module that has the same functions but accepting ValueTask as return value

[abelbraaksma]

Yeah, that's a good idea. I'll have to think a bit about how to implement, as it is likely to blow up the surface area.

Do note that taskSeq and IAsyncEnumerable uses ValueTasks already.