This PR defines `Vector.flatMap`, changes the order of arguments in
`List.flatMap` for consistency, and aligns the lemmas for
`List`/`Array`/`Vector` `flatMap`.
This PR completes aligning `List`/`Array`/`Vector` lemmas about
`flatten`. `Vector.flatten` was previously missing, and has been added
(for rectangular sizes only). A small number of missing `Option` lemmas
were also need to get the proofs to go through.
This PR adds basic lemmas about lexicographic order on Array and Vector,
achieving parity with List.
Many lemmas are still missing for all three, particularly about how
order interacts with `++`.
This PR adds lemmas about `Vector.set`, `anyM`, `any`, `allM`, and
`all`.
With these additions, `Vector` is now as in-sync with the `List` API as
`Array` is, and in future I'll be updating both simultaneously.
This PR upstreams lemmas about `Vector` from Batteries.
I'll be adding more soon, and PRs are welcome, particularly from those
who have previously contributed to `Vector` in Batteries.
