Add distributeListOverDynPure, export distributeMapOverDynPure

[spl]

I've found distributeListOverDynPure to be a very useful function that is non-trivial to write. I think it would be a good addition to distributeDMapOverDynPure and distributeMapOverDynPure. The latter was not exported and documented strangely (possibly a copy-paste error), so I exported it and updated the documentation.

[mightybyte]

👍 I always wondered why we only had the DMap version of this!

[ryantrinkle]

Thanks!

[lingnand]

What's the difference between distributeListOverDyn in Reflex.Class vs distributeListOverDynPure in Reflex.Dynamic? (from what I see, there's no difference)

The Pure suffix seems a bit awkward given the already long name. I'd suggest change the name of distributeMapOverDynPure to just distributeMapOverDyn and move it into Reflex.Class; then all distribute functions will be in one place.

[ryantrinkle]

Good point! In general, the functions with 'Pure' in their name are ones that originally had a monadic version, and I am doing a deprecation cycle to get rid of the monadic version - so the Pure version is simply the non-Pure version, minus an invocation of return. However, in this case, I think there's no actual deprecation cycle needed.