I don't think this is necessary, given this:
|2.2. HTML Lexical Syntax
[...]
| A complete discussion of SGML parsing, e.g. the mapping of a
| sequence of characters to a sequence of tags and data, is
| left to the SGML standard[SGML]. This section is only a
| summary.
I've never seen users try to stick comments inside tags or anything
like that, and DTD syntax is no worry: this document is not about how
to read/write SGML DTDs.
If you feel strongly about this, let me (and the list*) know.
* I'm getting feedback on these drafts just to me and not to the
list. This is a NO-NO. I don't guarantee to integrate any feedback
that you're not proud enough about to send to the whole list. Besides:
when you send it to the list, it goes in the archive and I like to
scan the archive for outstanding issues.
Dan