code: public List<VocabularyWord> words() {
          List<VocabularyWord> vocab = new ArrayList<>(vocabulary.values());
          Collections.sort(vocab, new Comparator<VocabularyWord>() {
              @Override
              public int compare(VocabularyWord o1, VocabularyWord o2) {
                  return Integer.compare(o2.getCount(), o1.getCount());
              }
          });
  
          return vocab;
      }
docs: Returns sorted list of words in vocabulary.
  Sort is DESCENDING.
  
  @return list of VocabularyWord