internal SuggestedWordItem(WordVocabularySource source, SuggestedWordItem previous, string word)
     : base(previous, source, word)
 {
     _previous = previous;
 }
 internal SuggestedWordItem(ITile predecessor, WordVocabularySource source, string word)
     : base(predecessor, source, word)
 {
     _previous = null;
 }
 internal ExtendedSuggestedWordItem(WordVocabularySource source, SuggestedWordItem previous, string wholeWord, string partWord)
     : base(source, previous, wholeWord)
 {
     _partWord = partWord;
 }