Rollup merge of rust-lang#25156 - rydotyosh:patch-4, r=alexcrichton

Remove printing of secret number at final source.

Author: steveklabnik

src/doc/trpl/guessing-game.md

@@ -965,8 +965,6 @@ fn main() {
 
     let secret_number = rand::thread_rng().gen_range(1, 101);
 
-    println!("The secret number is: {}", secret_number);
-
     loop {
         println!("Please input your guess.");