Fix up the white space damage from Nick Sayer's commit.

It's not technically required, but it keeps things looking nice, and much
easier to understand. This is important if people are going to be able
to learn DocBook by looking at the Handbook. It also makes it easier
to follow the structure if you don't have an SGML savvy editor.

I'm going to be *at least* as anal about this as bde is about style(9).
Sorry folks :-)