Leaving Freenode behind

[Stefan Kangas]

As you may have heard, the Freenode IRC network has been taken over by
a hostile corporate entity.[1][2]  The #emacs community has already
moved.[3]

I suggest we stop promoting it in Emacs, and instead promote the
community run Libera Chat.[4]  This would mean removing most
references and links to Freenode in our sources and documentation.

Are there any objections to this plan?  If not, I will be happy to go
ahead and make the necessary changes.

Footnotes:
[1] https://www.kline.sh/
[2] https://fuchsnet.ch/privat/fn-resign-letter.txt
[3] https://www.emacswiki.org/emacs/EmacsChannel#h5o-9
[4] https://libera.chat/