Spike: research documentable rendering order for K1 vs K2

[whyoleg]

During migration to Dokka K2 analysis some of the libraries we found some inconsistencies in sorting in different places. They are caused by different sorting of declarations of underlying implementations: Kotlin Compiler internals in K1 and Kotlin Analysis API in K2).
Before deciding on what and when to do with them we need to research what is affected.

This is a prerequisite for #3590

[vmishenev]

Note: This can be done during testing.