Recognise *.element.io links as Element permalinks

This ensures all Elements detect permalinks to official deployments as Element
and handle them internally.

Fixes https://github.com/vector-im/element-web/issues/16005

src/linkify-matrix.js

@@ -188,7 +188,8 @@ const escapeRegExp = function(string) {
 matrixLinkify.ELEMENT_URL_PATTERN =
     "^(?:https?://)?(?:" +
         escapeRegExp(window.location.host + window.location.pathname) + "|" +
-        "(?:www\\.)?(?:riot|vector)\\.im/(?:app|beta|staging|develop)/" +
+        "(?:www\\.)?(?:riot|vector)\\.im/(?:app|beta|staging|develop)/|" +
+        "(?:app|beta|staging|develop)\\.element\\.io/" +
     ")(#.*)";
 
 matrixLinkify.MATRIXTO_URL_PATTERN = "^(?:https?://)?(?:www\\.)?matrix\\.to/#/(([#@!+]).*)";