editorial: Use new HTML activation model

Adapt to whatwg/html#5129 and follow the spec editing advice from
https://docs.google.com/document/d/14wT89JZ0qeRehXGkcn3_meXxjvlHKgM9d7aJj80kQcQ/edit ("User
Activation: Guidance for spec authors") by replacing "triggered by user
activation" with "the current global object has transient activation".

This makes ReSpec happy again.

index.html

@@ -291,8 +291,8 @@ <h2>
           <li>If |state| is {{PermissionState["prompt"]}}, run the following
           steps:
             <ol>
-              <li>If these <a>obtain permission</a> steps were not <a>triggered
-              by user activation</a>, return {{PermissionState["denied"]}}.
+              <li>If the <a>current global object</a> does not have [=transient
+              activation=], return {{PermissionState["denied"]}}.
               </li>
               <li>Return the result of <a>requesting permission to use</a> with
               |permissionDesc|.
@@ -305,12 +305,11 @@ <h2>
         <aside class="note">
           In the case the steps are run from a dedicated worker, then the
           <a>current global object</a> is a {{DedicatedWorkerGlobalScope}},
-          which means that the <a>obtain permission</a> steps can never be
-          <a>triggered by user activation</a>, meaning that in order to use
-          wake locks from a dedicated worker, prior permission needs to granted
-          from the <a>browsing context</a> who created it, e.g. the <a>browsing
-          context</a> that is exists in the {{DedicatedWorkerGlobalScope}}'s
-          [=WorkerGlobalScope/owner set=].
+          which means that it will never have [=transient activation=].
+          Consequently, in order to use wake locks from a dedicated worker,
+          prior permission needs to be granted from the <a>browsing context</a>
+          who created it, e.g. the <a>browsing context</a> that is exists in
+          the {{DedicatedWorkerGlobalScope}}'s [=WorkerGlobalScope/owner set=].
         </aside>
       </section>
     </section>