"Optional Values" section in basics.md uses `println!("first value {}", first.unwrap())` without explaining why we don't need to dereference `first.unwrap()`

[josephrocca]

Title pretty much explains it. I was going to do a pull request but wasn't sure how to explain it (I'm a rust newb).

I found this: https://stackoverflow.com/questions/27852613/why-does-printing-a-pointer-print-the-same-thing-as-printing-the-dereferenced-po?rq=1