Convert the Delegated annotation into AdaptiveExpect

[toth-istvan-zoltan]

The duplicated annotations are quite ugly and unnecessary:

@Adaptive
@Delegated
fun someFun() {
}

Convert this into:

@AdaptiveExpect
fun someFun() {
}

• [x] actual class rename
• [x] update documentation (delegation.md -> expect.md)
• [x] make annotation meta (annotate the annotation with @Adaptive)
• [x] update the compiler plugin