Redundant property setter

Reports redundant property setters.

Setter is considered to be redundant in one of the following cases:

1. Setter has no body. Accessor visibility isn't changed, declaration isn't external and has no annotations.

   var myPropWithRedundantSetter: Int = 0 set // redundant var myPropA: Int = 0 private set // OK - property visibility is changed to private var myPropB: Int = 0 external set // OK - implemented not in Kotlin (external) var myPropC: Int = 0 @Inject set // OK - accessor is annotated

2. Setter body is a block with a single statement assigning the parameter to the backing field.

   var prop: Int = 0 set(value) { // redundant field = value }