This is a sample page of possible 'cleaner' syntax conversions.

<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\">

<code><!DOCTYPE html PUBLIC ...></code>
<pre><!DOCTYPE html TEST...></pre>
<verbatim><!DOCTYPE html TEST2...></verbatim>
<test><!DOCTYPE html TEST3...></test>

---+ Heading 1
---++ Heading 2
---++++++ Heading 6