Macros should find the default values

[Methrat0n]

Bug

final case class User(username: String = "Methrat0n")

object User {
 implicit val schema: Schema[User] = Schema.of[User]
}

Should be equivalent to

final case class User(username: String = "Methrat0n")

object User {
 implicit val schema: Schema[User] =
   "username".as[String].defaultTo("Methrat0n")
}

The same goes for the other macro modes.