Converter:

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

j2k/tests/testData/ast/class/privateInit.kt

@@ -1,4 +1,4 @@
 public open class MyClass() {
-private fun init(arg1 : Int, arg2 : Int, arg3 : Int) : Unit {
+private fun init(arg1 : Int, arg2 : Int, arg3 : Int) {
 }
 }