bpo-41983: add availability info to socket docs (GH-27519) (GH-29136)

* add availability info to AF_PACKET section
* add availability for AF_QIPCRTR as well

(cherry picked from commit 51375388bee7287be2d942906b48c8cf3f691e8b)

Co-authored-by: andrei kulakov <andrei.avk@gmail.com>
1 file changed