Clean up and unify exercises

exercises/14_generics/generics1.rs

@@ -1,10 +1,5 @@
-// generics1.rs
-//
 // This shopping list program isn't compiling! Use your knowledge of generics to
 // fix it.
-//
-// Execute `rustlings hint generics1` or use the `hint` watch subcommand for a
-// hint.
 
 fn main() {
     let mut shopping_list: Vec<?> = Vec::new();

exercises/14_generics/generics2.rs

@@ -1,10 +1,5 @@
-// generics2.rs
-//
 // This powerful wrapper provides the ability to store a positive integer value.
 // Rewrite it using generics so that it supports wrapping ANY type.
-//
-// Execute `rustlings hint generics2` or use the `hint` watch subcommand for a
-// hint.
 
 struct Wrapper {
     value: u32,