Add more examples to explain Dereferencing

[sb1752]

Perhaps there can be more quiz questions or links to Rust Playground. Possibly another section 9.2.

[edilmedeiros]

What feedback or observations from office hours do you have regarding that?

[sb1752]

Yes, this was just one person that mentioned it in the weekly feedback form and another during office hours. I wanted to make sure this wasn't too confusing since I mentioned it so briefly in the course.

Maybe the quiz does a decent job of getting that idea across? Maybe there's a good additional reading material I can add to the end.

I also had an idea for something in Rust playground in which we take two structs (Foo and Bar) and implement the Deref trait on one of them to showcase how this works. Maybe I can add that as an example to follow at the end of the section, but we haven't introduced Structs yet.

This probably doesn't warrant a section 9.2 though now that I think about it, that might be too much.