What are the rules around when to use `@SinceKotli...

# kontributors

[Renee Vandervelde]

What are the rules around when to use @SinceKotlin and what version to target when using it?
i.e. Should it be used any time a public method is added? and do the same rules apply to libraries like kotlin.test in addition to stdlib?

[turansky]

This information is helpful in docs

[turansky]

Public api must be marked