Point readers to Libera Chat IRC

The #git channel on Freenode does not have an active user base anymore.
Match the recommended IRC network of <https://git-scm.com/community>.

Author: knittl

book/01-introduction/sections/help.asc

@@ -18,7 +18,7 @@ $ git help config
 ----
 
 These commands are nice because you can access them anywhere, even offline.
-If the manpages and this book aren't enough and you need in-person help, you can try the `#git` or `#github` channel on the Freenode IRC server, which can be found at https://freenode.net[].
+If the manpages and this book aren't enough and you need in-person help, you can try the `#git`, `#github`, or `#gitlab` channels on the Libera Chat IRC server, which can be found at https://libera.chat/[].
 These channels are regularly filled with hundreds of people who are all very knowledgeable about Git and are often willing to help.(((IRC)))
 
 In addition, if you don't need the full-blown manpage help, but just need a quick refresher on the available options for a Git command, you can ask for the more concise "`help`" output with the `-h` option, as in: