Create a par_iter method on Query

[alice-i-cecile]

What problem does this solve or what need does it fill?

Getting data out of parallel iterators over Queries using par_for_each is very complex, due to limitations on ownership.

What solution would you like?

Create a par_map method on Query, which returns an iterator.

What alternative(s) have you considered?

Pre-allocate the data, then use par_for_each_mut to mutate the pre-allocated data.

[TheRawMeatball]

If it's returning an iterator, then it'd be more accurate to call it par_iter. Also, this is already pretty much there in my unkempt PR #2088

[TheRawMeatball]

It's currently waiting on some sort of resolution to the problems outlined here: #2093 (comment)

[rparrett]

Can this be closed?

[alice-i-cecile]

https://docs.rs/bevy/latest/bevy/ecs/system/struct.Query.html#method.par_iter

Yep!