[ANN] erc-irc-format: Erc extensions for IRC formatting codes

Hello Erc'ers,

With some help from folks on #emacs (special thanks to mekeor &
kickingvegas), I've refactored my old 'erc-ircfmt' snippet into an
installable Emacs package, now available from
https://github.com/fmqa/erc-irc-format

This package supplements Erc with a transient [1] menu for inputting IRC
formatting codes [2].

As an addition, the package also includes an Erc module 'erc-normalize'
for preserving formatting codes when yanking to Erc's input region.

The code has been tested under Emacs 29.1+ and Erc 5.6. Note that it is
recommended to upgrade the built-in transient package in order to fix a
number of superfluous warnings that are emitted on load when using older
versions of transient.el (see the README for a quick way to do this).

Future plans include investigating/implementing support for Emacs 28,
and, depending on uptake/feedback, preparation for contribution to Erc.

Cheers,
-A

[1] https://www.gnu.org/software/emacs/manual/html_mono/transient.html
[2] https://modern.ircdocs.horse/formatting