[guessing-game] finishing touches

# rust learning

## About this project

This project is the product of me following along with the Rust Book, using Brown University's interactive version found at https://rust-book.cs.brown.edu/experiment-intro.html. This version of the book includes interactive content, such as quizzes, to be completed as you read.

Enjoy!

    let secret_number: u8 = rand::random_range(1..=100);

    println!("The secret number is {secret_number}"); // debug purposes

    // println!("The secret number is {secret_number}"); // debug purposes

    println!("Please input your guess. (Hint: the number will be between 1 and 100.)");