docs: public static <T> ConsoleAnnotator<T> combine(Collection<? extends ConsoleAnnotator<? super T>> all) {
          switch (all.size()) {
          case 0:     return null;    // none
          case 1:     return  cast(all.iterator().next()); // just one
          }
  
          return new ConsoleAnnotatorAggregator<>(all);
      }