Typo in 3_5_Classifying_Yelp_Review_Sentiment.py

Hi, thanks for providing the code. I found a small typo in ```3_5_Classifying_Yelp_Review_Sentiment.py```. In the ReviewVectorizer class, the comment of ```vectorize``` should be one-hot rather than one-hit.

<img width="609" alt="Screen Shot 2021-03-26 at 11 03 08 PM" src="https://user-images.githubusercontent.com/19467235/112711683-7172a500-8e87-11eb-82c0-48c812e7e584.png">
