PRIVMSG: X@Y target rules

[DanielOaks]

This is still used with NICKSERC/NS/CS commands, and users can usually send PRIVMSGs to something like chanserv@services.freenode.net or whatever.

However, if they are still processed otherwise, they may be mostly restricted to IRC Operators. Especially ones that go to multiple targets.

Thanks to @sdaugherty for pointing this out

[ailin-nemui]

these rules/recommendations make it very unlikely that someone other than the server admin can read your passwords in case services are down and the server does not support U:lines (or sometimes Q:lines) to jupe nicks; or if the user sends it on the wrong network