Update chat archive status

Author: janbrasna

whatwg.org/chat

@@ -45,7 +45,7 @@
 
 <ul>
  <li><a href="https://matrixlogs.bakkot.com/WHATWG/">https://matrixlogs.bakkot.com/WHATWG/</a> (Matrix room)</li>
- <li><a href="https://view.matrix.org/room/!AGetWbsMpFPdSgUrbs:matrix.org/">https://view.matrix.org/room/!AGetWbsMpFPdSgUrbs:matrix.org/</a> (Matrix room)</li>
+ <li><a href="https://view.matrix.org/room/!AGetWbsMpFPdSgUrbs:matrix.org/">https://view.matrix.org/room/!AGetWbsMpFPdSgUrbs:matrix.org/</a> (older Matrix archive; not updated since 2021-07)</li>
  <li><a href="https://matrixlogs.bakkot.com/irc-whatwg/">https://matrixlogs.bakkot.com/irc-whatwg/</a> (former IRC channel; until 2021-06-14)</li>
  <li><a href="https://krijnhoetmer.nl/irc-logs/">https://krijnhoetmer.nl/irc-logs/</a> (former IRC channel; not updated since 2016-04)</li>
 </ul>