Correct email link, heading misuse, and trailing newline in irc.md

Thanks user seifferth for bringing this to my attention.

This patch is provided to Tilde.club under the terms of
GNU General Public License, any version
published by the Free Software Foundation.

wiki/source/irc.md

@@ -78,5 +78,4 @@ To connect to your ZNC its at services.tilde.club   Port: 6699(SSL)
 
 NOTE: long passwords fail to authenticate with the ZNC server.
 
-### Users created before December 28th, 2021 will need to email [mailto:root@tilde.club](root@tilde.club) to get your user added. 
-
+<big>**Users created before December 28th, 2021 will need to email <root@tilde.club> to get your user added.**</big>