review request: changing the default ifconfig(8) address format to CIDR

hi,

i've just submitted this PR:

https://github.com/freebsd/freebsd-src/pull/1216

which contains this commit:

commit 57d273c90ee1c17446236aba25ed0bd291c4f126 (HEAD -> lf/main, hemlock/lf/main)
Author: Lexi Winter <lexi@le-Fay.ORG>
Date:   Sat May 4 16:11:21 2024 +0100

    ifconfig(8): change default IP address format to 'cidr'

    'netmasks' haven't been used in IP networking for decades.  Change the
    default address format for both IPv4 and IPv6 addreses in ifconfig(8) to
    'cidr', which prints addreses in the format most users will be more
    familiar with.

    The previous format is still available using -finet:hex or -finet6:numeric.

imp@ suggested i should ask arch@ and net@ about this, so here i am!

i understand there might be some backward-compat concerns with scripting
here, but it's well past time this change was made, and anyone who
really can't update their scripts can use ifconfig -f or
$IFCONFIG_FORMAT to retain the old behaviour.