Marks Objective-C and Swift interoperability API as Beta.

The marked API has official Beta stability level, is considered to be a vital part of Kotlin/Native and Kotlin Multiplatform, and is evolved in a backward-compatible manner with the proper migration paths for incompatible changes.

It may partially lack the concise semantics, documentation, and API to interoperate with Swift and Objective-C features that do not have a direct Kotlin counterpart.

This API is recommended to be used for interoperability purposes, but with the API availability scope confined and narrowed down.