Fix: Remove multiple enum owner imports

[jkciesluk]

Previously exhaustive match completion on enum created multiple imports of enum owner

package withenum {
enum Color(rank: Int):
  case Red extends Color(1)
  case Blue extends Color(2)
  case Green extends Color(3)
}

package example
object Main {
  val x: withenum.Color = ???
  x match@@
}

Resulted in

import withenum.Color
import withenum.Color
import withenum.Color

package withenum {
enum Color(rank: Int):
  case Red extends Color(1)
  case Blue extends Color(2)
  case Green extends Color(3)
}

package example
object Main {
  val x: withenum.Color = ???
  x match@@
}

Now, we do distinct on additional edits so duplicates will be removed