Clean up and unify exercises

exercises/22_clippy/clippy1.rs

@@ -1,13 +1,8 @@
-// clippy1.rs
-//
 // The Clippy tool is a collection of lints to analyze your code so you can
 // catch common mistakes and improve your Rust code.
 //
 // For these exercises the code will fail to compile when there are Clippy
 // warnings. Check Clippy's suggestions from the output to solve the exercise.
-//
-// Execute `rustlings hint clippy1` or use the `hint` watch subcommand for a
-// hint.
 
 use std::f32;
 

exercises/22_clippy/clippy2.rs

@@ -1,8 +1,3 @@
-// clippy2.rs
-// 
-// Execute `rustlings hint clippy2` or use the `hint` watch subcommand for a
-// hint.
-
 fn main() {
     let mut res = 42;
     let option = Some(12);

exercises/22_clippy/clippy3.rs

@@ -1,7 +1,4 @@
-// clippy3.rs
-// 
 // Here's a couple more easy Clippy fixes, so you can see its utility.
-// No hints.
 
 #[allow(unused_variables, unused_assignments)]
 fn main() {