IRCv3 support

[xKevin04]

IRCv3 introduces features that alter the PRIVMSG structure. So far, I've only noticed labeled responses to interfere: https://ircv3.net/specs/extensions/labeled-response
Networks with IRCv3 support can be found here: https://ircv3.net/support/networks

I'm on tilde.chat myself and modified the workaround by @silv3rr (see #65 (comment)) to work there. So adding this to the top of fish_10.mrc should fix both issues:

on *:PARSELINE:out:*PRIVMSG *:{
  var %matches = $regsub($parseline,/^(?:.*? )?C?PRIVMSG (\S+).*$\n/m,\1,%privmsgtarget)
  if (%matches == 1 && $len($dll(%FiSH_dll,FiSH_GetKey10,$network %privmsgtarget))) > 1) {
    noop $regsubex(pl,$parseline,^(?:.*? )?C?(PRIVMSG \S+)(?: #\S+)?( :.*)$,\1 \2,&pl)
    if ($bvar(&pl,0) > 11) {
      .parseline -ob &pl
    }
  }
}

This essentially just removes all the extra stuff before PRIVMSG prior to sending it, in addition to the CPRIVMSG replacement. May not work on other networks and there could be more features that break functionality in different ways.

[flakes]

For incoming messages it's already been supported for many years, but apparently not for outgoing ones ...

[flakes]

New version released today, including a fix for this issue, please test, and open a new issue if required 😝