I do have to say that all of the doc tools they mention in the beginning are worse than Astro Starlight[1] and Vitepress[2]. Can highly recommend Astro Starlight for documentation sites, used it for multiple projects myself.

[1]: https://starlight.astro.build/

[2]: https://vitepress.dev/

Can vouch for Starlight and Astro in general. Don't be fooled by the fact that they are npm packages: Astro is geared for content-heavy websites and produces zero-JS bundles by default (i.e., if you just use markdowns without any script tags or JS frontend libraries, then there will be no JS in the final output at all).