How to add additional markdown content to Dokka-generated (Kotlin KDoc) documentation?

Question

I'm trying to add additional documentation pages (not tied to a class or package element) to a Dokka-generated documentation tree. I know that I can add a module.md or a file for each package, but if I want to add additional pages (e.g. an onboarding guide, etc) is there a way to write a separate user-guide.md (or equivalent) and include it in the documentation tree?