<foo
   id="bar">
   ...

changed to

<foo id="bar">
   ...

Before people complain that "Hang on, now you can't find out what the
allocated ID values are with a simple 'grep'" I'll say that's not a
problem. I plan to introduce a target in the Makefile (probably
something like 'handbook.id' which will automatically generate this
list doing a proper SGML parse.