Set current entry earlier in "traverse the history"

It was inconsistent with pushState() and could actually be observed due
to synchronous event dispatch.

This also makes a clarifying change to consistently refer to the
substeps of a particular step.

Fixes #1511.

source

@@ -83073,6 +83073,8 @@ State: <OUTPUT NAME=I>1</OUTPUT> <INPUT VALUE="Increment" TYPE=BUTTON O
  <span>URL</span>'s <span data-x="concept-url-fragment">fragment</span> is non-null, then
  <span>scroll to the fragment</span>.</p></li>
 
+ <li><p>Set the <span>current entry</span> to <var>entry</var>.</p></li>
+
  <li><p>Let <var>targetRealm</var> be the <span>current Realm Record</span>.</p></li>
 
  <li><p>If <var>entry</var> has a <span>state object</span>, then let <var>state</var> be
@@ -83090,9 +83092,9 @@ State: &lt;OUTPUT NAME=I>1&lt;/OUTPUT> &lt;INPUT VALUE="Increment" TYPE=BUTTON O
 
  <li>
 
- <p>If the <i>non-blocking events</i> flag is not set, then run the following steps
- <span>immediately</span>. Otherwise, the <i>non-blocking events</i> flag is set; <span>queue a task</span>
- to run the following substeps instead.</p>
+ <p>If the <i>non-blocking events</i> flag is not set, then run the following substeps
+ <span>immediately</span>. Otherwise, the <i>non-blocking events</i> flag is set; <span>queue a
+ task</span> to run the following substeps instead.</p>
 
  <ol>
 
@@ -83119,8 +83121,6 @@ State: &lt;OUTPUT NAME=I>1&lt;/OUTPUT> &lt;INPUT VALUE="Increment" TYPE=BUTTON O
 
  </li>
 
- <li><p>Set the <span>current entry</span> to <var>entry</var>.</p></li>
-
  </ol>
 
  <p>The <span>task source</span> for the tasks mentioned above is the <span>DOM manipulation task