Building the docs now works the same way, no matter when it happens - in
a cloned repo or distributed version.
This means all the relative links keep working; and that users or
downstream distributors can rebuild the docs with extra scripts or .rst
files in place.
Finally, it eliminates a large number of potential bugs which only occur
in one build environment and are difficult to reproduce.
Also add headings and this work to future news.
PeridexisErrant