Support umode +B for bots

[Grinnz]

unreal and related ircds support +B as an opt-in usermode, which then shows up in RPL_WHOREPLY and RPL_WHOISBOT. This is highly useful for bots that wish to automatically ignore other bots. Please consider supporting this, or an equivalent mechanism. Thank you.

[jesopo]

it feels like bot modes are just to make up for the fact that bots should output on NOTICE but don't

[Grinnz]

Yes, but this is not possible to fix, since clients do not treat notices acceptably for channel bots to use.

[xfnw]

[...] clients do not treat notices acceptably [,,,]

is this still a real problem? i've used quite a few clients (catgirl, weechat, irssi, hexchat, kirc, thelounge, kiwi, etc) and never had any that do anything unacceptable/weird on NOTICE

[Grinnz]

Not unacceptable necessarily, but inappropriate for receiving a reply from a bot in a channel. Such as popups, separate windows, alerts, etc.

[Mikaela]

Spec: https://ircv3.net/specs/extensions/bot-mode