Document sphinx hook and possibly add into package

[foster999]

Document the docs conf.py hook used in the package docs to generate output logs as part of a sphinx build.

[foster999]

It might be worth rewriting the tool as a sphinx extension if the need for this becomes apparent (please shout if interested).

Until then, see the bottom of sphinx conf.py for examples of hooking assumptions into a sphinx documentation build. Alternatively, the CLI could be called from the sphinx make file.