Fixed LUSERS count not subtracting invisible users

irc/handlers.go

 			opercount++
 		}
 	}
-	rb.Add(nil, server.name, RPL_LUSERCLIENT, client.nick, fmt.Sprintf(client.t("There are %[1]d users and %[2]d invisible on %[3]d server(s)"), totalcount, invisiblecount, 1))
+	rb.Add(nil, server.name, RPL_LUSERCLIENT, client.nick, fmt.Sprintf(client.t("There are %[1]d users and %[2]d invisible on %[3]d server(s)"), totalcount - invisiblecount, invisiblecount, 1))
 	rb.Add(nil, server.name, RPL_LUSEROP, client.nick, fmt.Sprintf(client.t("%d IRC Operators online"), opercount))
 	rb.Add(nil, server.name, RPL_LUSERCHANNELS, client.nick, fmt.Sprintf(client.t("%d channels formed"), server.channels.Len()))
 	rb.Add(nil, server.name, RPL_LUSERME, client.nick, fmt.Sprintf(client.t("I have %[1]d clients and %[2]d servers"), totalcount, 1))