Update Sphinx section

[smangham]

• Sphinx no longer adds the import and directory structure bits to the default setup file, but still needs them
• By default, Sphinx only includes class-level docstrings and not the __init__ ones, which clashes with VSCode which only auto-shows __init__ docstrings and not class-level ones. We can change this by adding autoclass_content = 'both'.
• We should mention readthedocs.io - people wanted to know how to convert the HTML into a website
• The default alabaster style is hard to read and has mimimal differentiation between blocks - we should introduce themes by for ewxample switching to classic.
• Learners didn't grok that the .rst files are just text files - we should get them to write a little intro
• They also all wanted to add multiple files to their docs, so a quick description of how to add extra automodules would be good.
• Some installations provide IPv6 links for the python server, we should specify localhost