have ToCs reflect only some headers in inclusions

Idea

+status

+priority

+tag

Probably want to show headers from inside cards that are titled/content/open view, but not closed view.

See the questions below.

Questions:

Have a ToC entry for the names of included cards in content view
...open view?
"Nest" headers of included cards - i.e., in the ToC show h1s as h2s, h2s as h3s?
(If so, we change their appearance in the page as well?)

+discussed in support tickets

+relevant user stories