netlink: Fix "version introduced" documentation

netlink(4) and associated features will exist in FreeBSD 14.0 but they
will also exist in 13.2, an older version, from commits such as 02b958b1
and b309249b.

This commit needs merging to stable/13 and releng/13.2.

MFC after: 2days (needs to be in RC2)
Reviewed by: imp,melifaro
Pull Request: https://github.com/freebsd/freebsd-src/pull/651
Approved by: re@ (cperciva)

(cherry picked from commit 6d2feb39ad)

share/man/man3/snl.3

@@ -297,7 +297,7 @@ and
 The
 .Dv SNL
 library appeared in
-.Fx 14.0 .
+.Fx 13.2 .
 .Sh AUTHORS
 This library was implemented by
 .An Alexander Chernikov Aq Mt [email protected] .

share/man/man4/genetlink.4

@@ -138,7 +138,7 @@ The following groups are defined:
 The
 .Dv NETLINK_GENERIC
 protocol family appeared in
-.Fx 14.0 .
+.Fx 13.2 .
 .Sh AUTHORS
 The netlink was implementated by
 .An -nosplit

share/man/man4/netlink.4

@@ -346,7 +346,7 @@ or
 .Re
 .Sh HISTORY
 The netlink protocol appeared in
-.Fx 14.0 .
+.Fx 13.2 .
 .Sh AUTHORS
 The netlink was implemented by
 .An -nosplit

share/man/man4/rtnetlink.4

@@ -525,7 +525,7 @@ RTNLGRP_NEIGH	Notifies on ARP/NDP neighbor  arrival/removal/change
 The
 .Dv NETLINK_ROUTE
 protocol family appeared in
-.Fx 14.0 .
+.Fx 13.2 .
 .Sh AUTHORS
 The netlink was implementated by
 .An -nosplit