gh-129994: update docs when using dualstack_ipv6 in socket.create_server (GH-129996)

(cherry picked from commit 044a1e1)

Co-authored-by: Alexander Ershov <[email protected]>

Author: AEErshov

Doc/library/socket.rst

@@ -838,10 +838,10 @@ The following functions all create :ref:`socket objects <socket-objects>`.
    , a default reasonable value is chosen.
    *reuse_port* dictates whether to set the :data:`SO_REUSEPORT` socket option.
 
-   If *dualstack_ipv6* is true and the platform supports it the socket will
-   be able to accept both IPv4 and IPv6 connections, else it will raise
-   :exc:`ValueError`. Most POSIX platforms and Windows are supposed to support
-   this functionality.
+   If *dualstack_ipv6* is true, *family* is :data:`AF_INET6` and the platform
+   supports it the socket will be able to accept both IPv4 and IPv6 connections,
+   else it will raise :exc:`ValueError`. Most POSIX platforms and Windows are
+   supposed to support this functionality.
    When this functionality is enabled the address returned by
    :meth:`socket.getpeername` when an IPv4 connection occurs will be an IPv6
    address represented as an IPv4-mapped IPv6 address.