An annotation argument which is another annotation value.
For example, with the following classes:
annotation class Bar(val s: String)
annotation class Foo(val b: Bar)
It is possible to apply such annotation:
@Foo(Bar("baz")). In this case, argument
Foo.b is represented by
AnnotationValue which annotation property contains all necessary information: the fact that it is a
Bar annotation (KmAnnotation.className) and that it has a "baz" argument (KmAnnotation.arguments).