Don't typealias Month (and others)

I suggest to not typealias anything in a multiplatform date/time library.

• It mixes platform-provided API into the library’s API which causes confusion and is platform-dependent.
• It doesn’t allow for adding a companion and thus “static” functionality - not even through extensions.

For example: I had code in the back-end that used Month.of(someInt). The code was relatively simple and there were no JVM-specific imports. So I’ve moved it to a shared multiplatform dependency and was surprised that Month.of() was no longer available. Month.<autocomplete> didn’t provide me with any useful alternative.

After Cmd-clicking on Month I’ve learned that it is merely a typealias on JVM. It took a while to figure out that there’s an additional Month(Int) function in kotlinx-datetime that I should’ve used instead. Scenarios like that can easily lead to confusion and inconsistency.

[JakeWharton]

@september669 the whole library requires coreLibraryDesugaring to be enabled enabling the use of java.time on previous API levels.

[fluidsonic]

With Kotlin 1.5 it became super annoying and really needs to be changed.