1. Note that settingumodes to be send to server on connect doesn't apply
until the next connect.
2. Future happened, so document two methods of setting umodes with
WeeChat, the old way (traditional would have messed lines) and new
modern way starting from 1.7+. I am not removing the old way as it
won't stop working and 1.7 is currently the git version. Also note
that the umodes can be set per-network.
3. Make ZNC also talk of traditional way (it fit without breaking lines)
and the modern way linking to issue about it and also clarify that
which networks the umodes affect depend on which levels you load
perform.
4. Add missing dot after umode +x which didn't have it even if the other
umode explanations had it.