TOC is a good idea on this one; since I wrote the original, I edit, 7 Nov 17
will try to free up time, soonest, to add one. offer TOC draft sample for comment and review.
FOR COMMENT: seems like a TOC with both a few keywords for each topic AND the markup needed would be appropriate... but a big PITA.
Update, 7 Nov 17 It was! The PITA is finding an appropriate, very brief description for the various parts of the TOC (and, in this case, deciding which elements of the main text to include to best serve users!
FWIW: Others have written technical approaches, using clever code to identify elements that may need to be included in a TOC. I went "manual" to deal with the issue I perceive (at least in the case of Markup in the Monastery; namely, that the so-called "Chapter...." headings are not, themselves, informative for someone seeking (for example) to know how to create a list. Also, when I created "Markup" originally, the various <Hn> tags were for formatting only, without due regard to nesting (I don't know of any commonly-used browser, even today, that cares) or syntactical relevance. Call me a dinosaur, but I still don't worry about that: even today, itelligibility of content trumps sytactical correctness.
Quis custodiet ipsos custodes. Juvenal, Satires