Chapter 21 formatting issues

## Describe what is not working with the course
There are some issues with the formatting in chapter 21. See screenshots below.

## Screenshots
![image](https://github.com/user-attachments/assets/66bcd7a3-bf76-4d7f-8213-78d0d6a22886)
Should be bullet points I think?

![image](https://github.com/user-attachments/assets/60d6ad44-c7a9-476f-abd4-7b82814e2fc1)


