Improve description of mod.SHARED.colPos_list

The property colPost_list has been reintroduced to 6.2 with commits:
241f4d0e8bc6568e6d48b084291afe23f5e203cd
20de0fc46b15f783b1884b9d7823617b838c9407
6a38987010ed732a4f25587fab52a39c336526d5

It is not considered deprecated any more, but can be used on top of Backend Layouts.

Releases: master, 6.2