Syntax: %bFORBID <nickname> [reason]%b

Prevents anyone from using %b<nickname>%b.  Anyone who uses
a forbidden nickname will be killed within 60 seconds if
they have not changed their nick. You can optionally
add %breason%b which can be seen with %bINFO%b command.
Forbidden nicknames can be cancelled through the %bUNFORBID%b
command or %bDROP%b command.
