Fix and clarify firing traverse navigate events

Some call sites were not correct in how they specified the target Navigation object. Also, add an assert about userInvolvementForNavigateEvents, and make a very long condition clause into a bulleted list.

Author: ADKaster

source

@@ -99033,8 +99033,8 @@ location.href = '#foo';</code></pre>
 
          <li><p>Let <var>navigateEventResult</var> be the result of <span data-x="fire a traverse
          navigate event">firing a traverse <code data-x="event-navigate">navigate</code>
-         event</span> at a <code>Navigation</code> <var>navigation</var> given
-         <var>targetEntry</var> and <var>userInvolvementForNavigateEvent</var>.</p></li>
+         event</span> at <var>navigation</var> given <var>targetEntry</var> and
+         <var>userInvolvementForNavigateEvent</var>.</p></li>
 
          <li><p>If <var>navigateEventResult</var> is false, then set <var>finalStatus</var> to
          "<code data-x="">canceled-by-navigate</code>".</p></li>
@@ -100883,15 +100883,37 @@ location.href = '#foo';</code></pre>
      data-x="she-document-state">document state</span>'s <span
      data-x="document-state-origin">origin</span>.</p></li>
 
-     <li id="descendant-navigable-traversal-navigate-events"><p>If <var>navigable</var> is not
-     <var>traversable</var>, and <var>targetEntry</var> is not <var>navigable</var>'s <span
-     data-x="nav-current-history-entry">current session history entry</span>, and
-     <var>oldOrigin</var> is the <span data-x="same origin">same</span> as <var>navigable</var>'s
-     <span data-x="nav-current-history-entry">current session history entry</span>'s <span
-     data-x="she-document-state">document state</span>'s <span
-     data-x="document-state-origin">origin</span>, then <span>fire a traverse <code
-     data-x="event-navigate">navigate</code> event</span> given <var>targetEntry</var> and
-     <var>userInvolvementForNavigateEvents</var>.</p></li>
+     <li id="descendant-navigable-traversal-navigate-events">
+      <p>If all of the following are true:</p>
+
+      <ul>
+       <li><p><var>navigable</var> is not <var>traversable;</var></p></li>
+
+       <li><p><var>targetEntry</var> is not <var>navigable</var>'s <span
+       data-x="nav-current-history-entry">current session history entry</span>; and</p></li>
+
+       <li><p><var>oldOrigin</var> is the <span data-x="same origin">same</span> as
+       <var>navigable</var>'s <span
+       data-x="nav-current-history-entry">current session history entry</span>'s <span
+       data-x="she-document-state">document state</span>'s <span
+       data-x="document-state-origin">origin</span>,</p></li>
+      </ul>
+
+      <p>then:</p>
+
+      <ol>
+       <li><p><span>Assert</span>: <var>userInvolvementForNavigateEvents</var> is not
+       null.</p></li>
+
+       <li><p>Let <var>navigation</var> be <var>navigable</var>'s <span
+       data-x="nav-window">active window</span>'s <span
+       data-x="window-navigation-api">navigation API.</span></p></li>
+
+       <li><p><span>Fire a traverse <code data-x="event-navigate">navigate</code> event</span> at
+       <var>navigation</var> given <var>targetEntry</var> and
+       <var>userInvolvementForNavigateEvents</var>.</p></li>
+      </ol>
+     </li>
 
      <li>
       <p>If <var>targetEntry</var>'s <span data-x="she-document">document</span> is null, or