New ask Hacker News story: Ask HN: What do people use for documentation sites these days?

Ask HN: What do people use for documentation sites these days?
4 by brundolf | 5 comments on Hacker News.
I have an upcoming need to document a large project (reference manual, tutorials, etc). I'm a web dev but I don't want to spend a ton of time making something custom. I assume there are popular, nice-looking static site generators out there for this type of thing. Should be free and self-hostable, and any special features for embedding code and such would be cool too. I don't need a CMS, in fact Markdown would be preferred. Any recommendations?