Converter:

Omit Unit return type
Refactor handling of Unit type: extract separate object UnitType

j2k/tests/testData/ast/enum/runnableImplementation.kt

@@ -4,7 +4,7 @@ BLACK
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-public override fun run() : Unit {
+public override fun run() {
 System.out?.println("name()=" + name() + ", toString()=" + toString())
 }
 }