iwm.4: add iwlwifi cross-reference

iwlwifi(4) supports a superset of the devices supported by iwm(4).  The
latter may be retired in the future (if there is no reason to prefer it
for the set of devices supported by both).

Sponsored by:	The FreeBSD Foundation

share/man/man4/iwm.4

@@ -23,7 +23,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd February 4, 2023
+.Dd February 20, 2024
 .Dt IWM 4
 .Os
 .Sh NAME
@@ -167,6 +167,7 @@ failed.
 This should not happen.
 .El
 .Sh SEE ALSO
+.Xr iwlwifi 4 ,
 .Xr iwmfw 4 ,
 .Xr pci 4 ,
 .Xr wlan 4 ,