docs: Description validate(Tree tree, VisitorState state) {
      GuardedByValidationResult result = GuardedByUtils.isGuardedByValid(tree, state);
      if (result.isValid()) {
        return Description.NO_MATCH;
      }
      return buildDescription(tree)
          .setMessage(String.format("Invalid @GuardedBy expression: %s", result.message()))
          .build();
    }