flatten : Avoid confusion

[vicuna]

Original bug ID: 7288
Reporter: tormen
Status: closed (set by @damiendoligez on 2016-09-27T14:21:19Z)
Resolution: fixed
Priority: normal
Severity: minor
Fixed in version: 4.04.0 +dev / +beta1 / +beta2
Category: documentation

Bug description

As Ocaml tends to be MINMAL in terms of functions in the std lib, I was a bit confused that there is List.flatten and List.concat.

This plus the fact that there was not ONLY written "Same as concat" for flatten made me wonder if they are in deed really 100% identical.

To effectively prevent such confusion I propose to simply remove the
" Not tail-recursive (length of the argument + length of the longest sub-list)."
and ONLY keep the sentence "Same as concat." :)

[vicuna]

Comment author: @damiendoligez

I've changed it to "An alias for concat." which is the terminology used elsewhere in the stdlib. (commit 5cc9300)