Replace if close watcher not null with assert

Author: lukewarlow

source

@@ -62726,18 +62726,14 @@ interface <dfn interface>HTMLDialogElement</dfn> : <span>HTMLElement</span> {
    <li><p><span data-x="list remove">Remove</span> <var>subject</var> from <var>subject</var>'s
    <span>node document</span>'s <span>open dialogs list</span>.</p></li>
 
-   <li>
-    <p>If <var>subject</var>'s <span data-x="dialog-close-watcher">close watcher</span> is not null,
-    then:</p>
+   <li><p><span>Assert</span>: <var>subject</var>'s <span data-x="dialog-close-watcher">close
+   watcher</span> is not null.</p></li>
 
-    <ol>
-     <li><p><span data-x="close-watcher-destroy">Destroy</span> <var>subject</var>'s <span
-     data-x="dialog-close-watcher">close watcher</span>.</p></li>
+   <li><p><span data-x="close-watcher-destroy">Destroy</span> <var>subject</var>'s <span
+   data-x="dialog-close-watcher">close watcher</span>.</p></li>
 
-     <li><p>Set <var>subject</var>'s <span data-x="dialog-close-watcher">close watcher</span> to
-     null.</p></li>
-    </ol>
-   </li>
+   <li><p>Set <var>subject</var>'s <span data-x="dialog-close-watcher">close watcher</span> to
+   null.</p></li>
   </ol>
 
   <h4><dfn>Dialog light dismiss</dfn></h4>