https://en.wikipedia.org/wiki/Markdown
There is no official Markdown specification and there are many different
implementations.
This seems intended by the creators of the language.
TODO
- count number of headings for each heading level
(loop through all headings, find the highest heading level, get all used levels
then create a slice or slice of maps and append after each deeper level discovered...) - add docs
- delph deeper into different Markdown implementations (like CommonMark)
- add support for "Setext-style headers"