Add Built-Ins `fgroupsof` and `fwindowsof` about coconut HOT 2 OPEN

Hmmm... this isn't really a Functor operation, so the name fgroupsof doesn't make a ton of sense, but I do see the use case.

If you just want a simple implementation for now, these should work pretty well:

def fgroupsof(n, obj) =
    range(0, len(obj), n) |> map$(start -> obj[start:start+n])

def fwindowsof(n, obj) =
    range(0, len(obj) - n + 1) |> map$(start -> obj[start:start+n])

from coconut.

Thanks for your answer, the names were indeed poorly chosen.
I know how to implement these, just wanted to know if the release of a built-in was an option.
Either new dedicated functions, or maybe an optionnal kwarg to preserve the type for the already existing functions?
It's not very important, just an idea :-)

from coconut.