code typos etc discovered by students

[damian0604]

(still need to check)

In Exercise 3, from keras.preprocessing.sequence import pad_sequences does not work. I used:
from keras_preprocessing.sequence import pad_sequences instead.

Exercises Week 9

1. In the "Initialize the pre-trained BERT model" section, there is a typo:
   from transformers import AutoTokenizer, AutoModelForSequenceClassification
   model = AutoModelForSequenceClassification.from_pretrained(model_nameame, num_labels=len(id2label)).to(device_name)

"model_nameame" should be "model_name" instead.

Chapter 11.5

1. In Example 11.14, "get_feature_names()" seems to be outdated. I fixed this by calling the newer version
   "get_feature_names_out()".