[thelist] Always use a DOCTYPE (was: Horizontal scrollbar in IE 6.0)

>> Removing either the DOCTYPE (or the link to the DOCTYPE) means that the
>> browser has no set of "rules" to adhere to when rendering the page.
>
> Not entirely true: they render the page in 'quirks mode'

... which is browser-specific and highly unreliable. While using a DOCTYPE
will influence Javascript, making sure that the Javascript is "valid" (i.e.
that it will work in current and legacy browsers) is a step forwards.

Regards
Mark Howells
<http://www.mark.ac/evl/>