FR: Show a note about CGNAT space

[johnmaguire]

It'd be great if CGNAT space (RFC 6598) 100.64.0.0/10 contained a note under "Hosts/Net" like RFC 1918 does.

❯ ipcalc 100.64.0.1
Address:   100.64.0.1           01100100.01000000.00000000. 00000001
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   100.64.0.0/24        01100100.01000000.00000000. 00000000
HostMin:   100.64.0.1           01100100.01000000.00000000. 00000001
HostMax:   100.64.0.254         01100100.01000000.00000000. 11111110
Broadcast: 100.64.0.255         01100100.01000000.00000000. 11111111
Hosts/Net: 254                   Class A

Compare to RFC 1918 space:

❯ ipcalc 192.168.0.1
Address:   192.168.0.1          11000000.10101000.00000000. 00000001
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   192.168.0.0/24       11000000.10101000.00000000. 00000000
HostMin:   192.168.0.1          11000000.10101000.00000000. 00000001
HostMax:   192.168.0.254        11000000.10101000.00000000. 11111110
Broadcast: 192.168.0.255        11000000.10101000.00000000. 11111111
Hosts/Net: 254                   Class C, Private Internet