Ignore hint in test – not sure we want to refactor this (yet) (dart-lang/yaml_edit#19)

diff --git a/pkgs/yaml_edit/test/random_test.dart b/pkgs/yaml_edit/test/random_test.dart
index 1b2f9e9..08207df 100644
--- a/pkgs/yaml_edit/test/random_test.dart
+++ b/pkgs/yaml_edit/test/random_test.dart
@@ -68,6 +68,7 @@
   /// Maximum depth of random YAML collection generated.
   final int maxDepth;
 
+  // ignore: unused_element
   _Generator({int? seed, this.maxDepth = 5}) : r = Random(seed ?? 42);
 
   int nextInt([int max = maxInt]) => r.nextInt(max);