[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 eaff9c3)

Co-authored-by: Nikita Sobolev <[email protected]>

Author: miss-islington

Doc/library/socket.rst

@@ -436,7 +436,8 @@ Constants
       ``TCP_FASTOPEN_CONNECT``, ``TCP_ULP``, ``TCP_MD5SIG_EXT``,
       ``TCP_FASTOPEN_KEY``, ``TCP_FASTOPEN_NO_COOKIE``,
       ``TCP_ZEROCOPY_RECEIVE``, ``TCP_INQ``, ``TCP_TX_DELAY``.
-      Added ``IP_PKTINFO``.
+      Added ``IP_PKTINFO``, ``IP_UNBLOCK_SOURCE``, ``IP_BLOCK_SOURCE``,
+      ``IP_ADD_SOURCE_MEMBERSHIP``, ``IP_DROP_SOURCE_MEMBERSHIP``.
 
 .. data:: AF_CAN
           PF_CAN