Invalid XHTML in docs

[jwakely]

The docs contain things like:

<h1><a class="toc-backref" href="./categorized-index.html#id1612"><a class="subsection-title" href="#concepts" name="concepts">Concepts</a></a></h1>

This is invalid, you cannot nest an <a> element inside another <a> element.

<ul class="simple" id="value-part">
<span id="key-part"></span><li>A <em>key</em> is a part of the element type used to identify and retrieve

This is invalid, you cannot have a <span> child of <ul>.

<pre class="literal-block">
typedef <a href="./begin.html" class="identifier">begin</a>&lt;Sequence&gt;::type i<sub>1</sub>;

You cannot have <sub> inside <pre> (there are other cases like this with <sup> too).

<ul class="toc simple" id="outline">
<li><a class="reference internal" href="./sequences.html" id="id1393">Sequences</a><ul class="toc" id="outline">
<li><a class="reference internal" href="./concepts.html" id="id1394">Concepts</a><ul class="toc" id="outline">

You cannot have multiple elements with the same id attribute.

<table border="1" class="docutils table" id="base">
<span id="second"></span><span id="first"></span><colgroup>
<col width="39%" />
<col width="61%" />
</colgroup>
<thead valign="bottom">

You can't have a <span> as a child of <table>.

These validation errors cause problems for packagers, as invalid XML is a potential security risk.

Either don't pretend the files are XML (e.g. change the doctype to HTML 5), or validate them and fix the errors please.

[jeking3]

@jwakely did you resolve all the issues with your PR?

[jwakely]

I think I fixed all the problems at the time. There might be new ones introduced since then, I haven't checked.