The documentation is ok for now, but there are a lot of details missing. And I suggest to make it easily possible to note these missing thing via comments. Example: the Annotations page doesn’t say something about parameters, default values or nested annotations.
Forking the page wouldn’t help, because most readers would only know that they don’t know what they want to know
Version Number in URIs
The documentation should explicitly reflect the Kotlin version. I suggest an URI scheme like this:
Whereas the latter should always point to the last stable release.
A search box on the documentation pages would be helpful.