Two immediate nits (and I mean these from a place of love — I am a sucker for docs tools):

- Your splash page's hero image is indistinguishable at first glance from basic Markdown. More than that, it's the kind of thing I'd expect a tool to _automatically_ generate!

- The idea of colocating documentation with the files its documenting is really interesting, and a core pain point of most internal docs ("what do I need to update when I change this file...?") I think your screenshot here can be much improved.