code: void addSuppression(String suppression) {
      lazyInitInfo();
  
      if (info.suppressions == null) {
        info.suppressions = ImmutableSet.of(suppression);
      } else {
        info.suppressions = new ImmutableSet.Builder<String>()
            .addAll(info.suppressions)
            .add(suppression)
            .build();
      }
    }
docs: Add a suppressed warning.