Schematron checks

[Shaun McCance <shaunm gnome org>]

I've just added a simple Schematron schema to gnome-help,
along with the script schematron.sh to run it across all
the page files. Just run the script and hope there's no
output.

Schematron is a validation language that works by stating
rules with XPath expressions. It's not supposed to be a
replacement for the RNG schemas. It augments them. And in
this case, it's holding special rules that are basically
just valid for this document.

At the moment, the only rule is that all pages must use
the standard legal.xml through XInclude.

The nice thing here is that we can add rules for whatever
constraints we want to enforce for a common style. If we
want <desc> elements to always end with a period, that's
a rule. Running the script will tell us all the offenders.

So, if you have anything in mind, let me know, and I can
add a rule to the Schematron file for it.

--
Shaun