Fix Kotlin API reference

[TomRHandcock]

The CSS formatting appears to have broken for the Dokka generated API reference (source) which makes the page largely unusable. The root cause appears to be 404 errors when the browser attempts to request the CSS stylesheets.

[mattmapadmi]

I think it's the whole thing has gone, but somehow the 404 page gets generated.

[mattmapadmi]

Dokka is saying there's no docs

Guessing we've updated Kotlin tooling at some point that has angered it.