[3.12] gh-89415: Mention new `IP_*` constants in `socket` module in the docs (GH-105266) (#105270)

gh-89415: Mention new `IP_*` constants in `socket` module in the docs (GH-105266)
(cherry picked from commit eaff9c39aa1a70d401521847cc35bec883ae9772)

Co-authored-by: Nikita Sobolev <mail@sobolevn.me>