FIxed IRC webclient URL

Somewhat ironic that it is me fixing this.

Author: smoe

docs/src/getting-started/about-linuxcnc.txt

@@ -50,8 +50,8 @@ It is a live connection to other LinuxCNC users.
 The LinuxCNC IRC channel is #linuxcnc on freenode.
 
 The simplest way to get on the IRC is to use 
-the embedded java client on this 
-https://webchat.freenode.net/?channels=%23linuxcnc[page].
+the embedded client on this
+https://web.libera.chat/#linuxcnc[page].
 
 .Some IRC etiquette