Update motd.txt (#37382)

Updates the link to reflect /vm/ being where the thread is and the fact that 4channel is kill

config-example/motd.txt

@@ -1,5 +1,5 @@
 <p><b><font size="32">Welcome to /vg/station</font></b>
-<b><font size = "4">The current thread can be found by <font color="purple"><a href="https://boards.4channel.org/vg/catalog#s=ss13g">(clicking here)</a></font></font><br></b>
+<b><font size = "4">The current thread can be found by <font color="purple"><a href="https://boards.4chan.org/vm/catalog#s=ss13">(clicking here)</a></font></font><br></b>
 <font size = "4">Server's byond version is: <a href="https://www.byond.com/docs/notes/515.html">515.1608</a></font>
 <font size = "4">Read the <a href="http://ss13.moe/wiki/">wiki,</a> and consider <a href="http://ss13.moe/wiki/index.php/Guide_to_Contributing_to_the_Wiki">contributing!</a></font><br>
 <font color="#DF0101" size=5>Donate to help keep the server running: <a href="http://ss13.moe/donate">Paypal</a> or <a href="http://patreon.com/pomf">Patreon</a>.</font><br>