Clarify unknown or null behavior

[kellyatradiantlabs]

@joshuamzm how do I get my new file defaulting_engine.rst to show up in the index of pages?

[joshuamzm]

@joshuamzm how do I get my new file defaulting_engine.rst to show up in the index of pages?

@kellyatradiantlabs I added the Sphinx link (without the first underscore) in the toctree section of the index file (fbf6302).

Now you can see your page linked in the ToC and in the sidebar.

I fixed the JSON code blocks formatting and couple typos in subsequent commits.