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;