Lowdown is fairly simple while supporting the PHP Extra extensions.
It also comes with extensive documentation in its man pages, for example
the whole language is described in lowdown(5).
See https://kristaps.bsd.lv/lowdown/
This fixes a big TODO (anchor links for the table of contents on the
webring page).
* add an empty footer
* add a minimal html header
* indent the nav
* modify the build process (publish.sh):
* use a tmp directory
* use discount markdown(1) rather than discount mkd2html(1)
* generate html page title from the file name
* indent html body
* use cat(1) to combine the pieces
* remove trailing newlines in publish.sh
* git ignore tmp/ directory
