I don't see why SRFI documents would be disqualified. That are existing documents that live on the web, they pertain to many Scheme implementations, and since those implementations often don't provide their own documentation for SRFI APIs, they substitute for that user documentation.
I agree that it would be great to have something Scheme-native, but I would love for our documentation to be part of
devdocs.io, too, both because I use
devdocs.io and because a Scheme presence in
devdocs.io is great advertising for the language and its implementations. Devdocs.io is popular, and seeing Scheme there, even in passing, might bring us a lot of newly interested folks.