FWIW, if you're going out to the nimbleverse already, it's already in
[adix/lptabz](https://github.com/c-blake/adix/blob/4f4e502125d75874a56de0a7a60298de7d1d5a53/adix/lptabz.nim#L1084)
and for small key spaces (like char or short-indexable) in
[adix/ditab](https://github.com/c-blake/adix/blob/4f4e502125d75874a56de0a7a60298de7d1d5a53/adix/ditab.nim#L428)
(as an `iterator` over the `topByVal`, not as a `proc`) { no need there to
build a `seq` (well, a `seq` _beyond_ the heap-structured `seq` already built
in `heapqueue`) }.
