Hmm I started at:

https://linux.die.net/man/8/ifconfig

which says "This program is obsolete! For replacement check ip addr and ip link" and references ip(8) in the See Also section. Neither page refers to ip-address. In fact that entry doesn't exist on die.net which seems to be what Google considers to be the authoritative source for Linux man pages.

I can’t vouch for the updatedness of “linux.die.net”, of which I know nothing. Try this one:

https://manpages.debian.org/testing/iproute2/ip-address.8.en...