Returns a list of Word objects that are the suggestions to any word.
If the word is correctly spelled, then this method
could return just that one word, or it could still return a list
of words with similar spellings.
Each suggested word has a score, which is an integer
that represents how different the suggested word is from the sourceWord.
If the words are the exactly the same, then the score is 0.
You can get the dictionary to only return the most similar words by setting
an appropriately low threshold value.
If you set the threshold value too low, you may get no suggestions for a given word.
This method is only needed to provide backward compatibility.