Javadoc jars empty or not present

**Describe the bug**

Javadoc jars are either not present (e.g. `kotlinx-coroutines-core`) or empty (e.g. `kotlinx-coroutines-core.jvm`) for some published modules, on Maven Central.  While they aren't hugely impactful, they are nice to have (and I'm attempting to write a MCP tool that lets agents use them for documentation).
