docbook message

Subject: RE: [docbook] namespace markup

I do think putting prefix back in as a possible value for the class
attribute of <tag> is a good idea.

References:
- RE: [docbook] namespace markup
  - From: "Peter Ring" <PRI@magnus.dk>
- Re: [docbook] namespace markup
  - From: Jirka Kosek <jirka@kosek.cz>
- RE: [docbook] namespace markup
  - From: "Johnson, Eric" <Eric.Johnson@iona.com>