add more alternative docs systems

 * [hugo](https://gohugo.io/): golang

 * [ikiwiki][]: previously used, old, Perl, hard to setup, occult   templating system, slow

 * [lektor](https://www.getlektor.com/): used at Tor for other public websites

 * [Mkdocs](https://www.mkdocs.org/): also supported by [Read the docs](https://readthedocs.org/), similar to

   Sphinx, but uses Markdown instead of RST

 * [Nanoc][]: [used by GitLab](https://docs.gitlab.com/ee/development/documentation/site_architecture/index.html)

 * [pelican](https://getpelican.com/): watch out for pelican, another user reports that,

   with caching, generating a 500 page site takes 30 seconds, 2

   minutes without caching

 * [Sphinx](https://www.sphinx-doc.org/): used by [Read the docs](https://readthedocs.org/), enforces more structure

   and more formal (if less familiar) markup (ReStructured Text, RST)

 * [zola](https://www.getzola.org/): rust

[Nanoc]: https://nanoc.ws/