Provides command completion for IRC clients that support it. This plugin implements an early draft of the IRCv3 autocompletion client tags. As this is not yet a released specification, it does nothing unless `supybot.protocols.irc.experimentalExtensions` is set to True (keep it set to False unless you know what you are doing). If you are interested in this feature, please contribute to [the discussion](https://github.com/ircv3/ircv3-specifications/pull/415)