Improve behavior for parsing option end tags

This moves the steps to clone an option element into a
selectedcontent element from the parsing of an option end tag to a
paragraph which specifies that this should happen any time an option is
popped off the stack of open elements, which will make the algorithm run
even if the author didn't explicitly write a closing option tag.

Fixes #11653.

Author: josepharhar

source

@@ -57212,6 +57212,12 @@ interface <dfn interface>HTMLOptionElement</dfn> : <span>HTMLElement</span> {
   </ol>
   </div>
 
+  <div algorithm>
+  <p>When an <code>option</code> element is popped off the <span>stack of open elements</span> of an
+  <span>HTML parser</span> or <span>XML parser</span>, the user agent must run <span>maybe clone an
+  option into selectedcontent</span> given the <code>option</code> element.</p>
+  </div>
+
   <dl class="domintro">
    <dt><code data-x=""><var>option</var>.<span subdfn data-x="dom-option-selected">selected</span></code></dt>
 
@@ -141427,17 +141433,6 @@ document.body.appendChild(text);
     <p><span>Insert an HTML element</span> for the token.</p>
    </dd>
 
-   <dt>An end tag whose tag name is "option"</dt>
-   <dd>
-    <p>Let <var>option</var> be the first <code>option</code> element in the <span>stack of open
-    elements</span>.</p>
-
-    <p>Run the steps for "any other end tag."</p>
-
-    <p>If <var>option</var> is no longer in the <span>stack of open elements</span>, then run
-    <span>maybe clone an option into selectedcontent</span> given <var>option</var>.</p>
-   </dd>
-
    <dt>A start tag whose tag name is one of: "rb", "rtc"</dt>
    <dd>
     <p>If the <span>stack of open elements</span> <span data-x="has an element in scope">has a