Missing sources in 5.0.0-alpha1

[ZacSweers]

Looks like this is just due to the switch to Kotlin. #256 will help this for those consuming from maven since it configures Dokka for you, but I'm not sure the gradle plugin publisher tool speaks Dokka

[fractalwrench]

I'm not sure that this is related to the switch to Kotlin as using the v4.7.5 plugin shows similar bytecode a Groovy example project. We'd accept #256 when it's passing CI, particularly if it resolves this issue - otherwise this work is scheduled for after v5's release.

[ZacSweers]

I'll try to get that working today or tomorrow!