Fix footnote ordering and some other bugs

org/testdata/example.html

@@ -24,7 +24,7 @@
 <ol>
 <li><p>and another subitem</p>
 <code class="src src-sh">
-<pre>echo with a block<pre>
+<pre>echo with a block</pre>
 </code>
 </li>
 <li><p>and another one with a table</p>
@@ -66,12 +66,12 @@
 </ul>
 <h2>blocks</h2>
 <code class="src src-bash">
-<pre>echo a bash source block<pre>
+<pre>echo a bash source block</pre>
 </code>
 <code class="src src-text">
 <pre>a source block without a language
 and a second line
-and a third one<pre>
+and a third one</pre>
 </code>
 <pre class="example">
 an example blockwith multiple lines
@@ -90,7 +90,51 @@ Mongodb is very webscale
 <div class="footnote-definitions">
 <div class="footnote-definition">
 <sup id="footnote-1">1</sup>
-<p>Foobar</p>
+<p><a href="https://www.example.com">https://www.example.com</a></p>
+<ul>
+<li>footnotes can contain <strong>markup</strong></li>
+<li><p>and other elements</p>
+<ul>
+<li><p>like blocks</p>
+<code class="src src-text">
+<pre>other non-plain</pre>
+</code>
+</li>
+<li><p>and tables</p>
+<table><tbody>
+<tr>
+<td>1</td><td>a</td>
+</tr>
+
+<tr>
+<td>2</td><td>b</td>
+</tr>
+
+<tr>
+<td>3</td><td>c</td>
+</tr>
+</tbody>
+</table>
+</li>
+</ul>
+</li>
+</ul>
+</div>
+<div class="footnote-definition">
+<sup id="footnote-3">3</sup>
+<p><a href="http://example.com/unused-footnote">example.com/unused-footnote</a> </p>
+</div>
+<div class="footnote-definition">
+<sup id="footnote-4">4</sup>
+<p>another unused footnote </p>
+</div>
+<div class="footnote-definition">
+<sup id="footnote-5">5</sup>
+<p>another unused footnote </p>
+</div>
+<div class="footnote-definition">
+<sup id="footnote-6">6</sup>
+<p>another unused footnote</p>
 </div>
 <div class="footnote-definition">
 <sup id="footnote-2">2</sup>