chore: clarify why visit it called before iterating

wait/walk.go

@@ -43,6 +43,7 @@ func walk(root *Strategy, visit VisitFunc) error {
 		return nil
 	}
 
+	// Allow the visit function to customize the behaviour of the walk before visiting the children.
 	if err := visit(*root); err != nil {
 		if errors.Is(err, VisitRemove) {
 			*root = nil