Zine v0.13.0
A few bugfixes and a small number of new features, including the new SuperMD restriction for headings mentioned in Table of Contents situation.
This new check has both discovered heading level skips that I did not intend to make, and it has also unearthed issues in the way I designed some of my websites where I would be very inconsistent with how I meant to present headings depending on the layout being used. Not super fun to fix, but now all these websites are much more straight-forward to edit than before.
