Hi, thank you for this great library!

I'm curious if you would consider adding an option to always derive enums as if they were sealed traits/sealed abstract classes? That is, even a simple enum with only singleton cases would still produce a JSON object and could be configured with AdtEncodingStrategy.

For example:

import io.bullet.borer.{Encoder, Json}
import io.bullet.borer.derivation.MapBasedCodecs.*

enum Foo derives Encoder {
  case Bar
}
Json.encode(Foo.Bar).toUtf8String // "Bar"

sealed trait Baz derives Encoder.All
object Baz {
  case object Quux extends Baz
}
Json.encode(Baz.Quux: Baz).toUtf8String // {"Quux":{}}

I would like Json.encode(Foo.Bar) to produce {"Baz":{}} so I can use enums and sealed traits interchangeably