Rename guide title

[mattgarrish]

Switches "EPUB Accessibility Metadata Guide" to "EPUB Accessibility — Schema.org Metadata Guide"

(An alternative would be "Package Document Metadata Guide" but that would only be needed if we were covering conformance metadata, which I don't think this guide was expected to get into?)

[clapierre]

This guide might get into conformance metadata, but at this point I don't think so.
Should we try to keep our options open?

EPUB Accessibility - Package Data Metadata Guide?

[mattgarrish]

Package Data Metadata Guide

Data and Metadata suggest the same thing. And now I wonder if we should use the "EPUB Accessibility" label in the CG. Maybe it would be safer to make it something like:

Guide to Expressing Accessibility Metadata in the EPUB Package Document

We could probably leave the short name and directory alone in this case, too. Does that work?

[mattgarrish]

Or even strip off "Guide to" from the start to make it a little shorter?

[clapierre]

Yeah, I kind of like "Expressing Accessibility Metadata in the EPUB Package Document"

[GeorgeKerscher]

I too like "Expressing Accessibility Metadata in the EPUB Package Document"

[mattgarrish]

I'm going to merge this for now and we can always continue to refine the title as we go.