Function
findNearestAncestor
Common
```kotlin
fun DelegatableNode.findNearestAncestor(key: Any?): TraversableNode?
```
Finds the nearest traversable ancestor with a matching `key`.
findNearestAncestor
Common
```kotlin
fun T.findNearestAncestor(): T? where T : TraversableNode
```
Finds the nearest ancestor of the same class and key.