Revert Util\Strings::escapeHtml changes from #7725

- Breaks display of inserted mentions

src/Util/Strings.php

@@ -68,7 +68,7 @@ class Strings
      */
     public static function escapeHtml($string)
     {
-        return htmlentities($string, ENT_QUOTES | ENT_HTML5, 'UTF-8', false);
+        return htmlspecialchars($string, ENT_COMPAT, 'UTF-8', false);
     }
 
     /**