Could `@ExperimentalTime` be removed from `*public...

# kotlinx-datetime

[CLOVIS]

Could @ExperimentalTime be removed from *public fun* Instant.Companion.*serializer*()?

[Dmitry Khalanskiy [JB]]

It's up to the kotlinx.serialization folks to decide, but in my opinion, there's no reason not to. Filed a PR: github.com/Kotlin/kotlinx.serialization/pull/3261