Clean up and unify exercises

exercises/01_variables/variables1.rs

@@ -1,9 +1,4 @@
-// variables1.rs
-//
 // Make me compile!
-//
-// Execute `rustlings hint variables1` or use the `hint` watch subcommand for a
-// hint.
 
 fn main() {
     x = 5;

exercises/01_variables/variables2.rs

@@ -1,8 +1,3 @@
-// variables2.rs
-//
-// Execute `rustlings hint variables2` or use the `hint` watch subcommand for a
-// hint.
-
 fn main() {
     let x;
     if x == 10 {

exercises/01_variables/variables3.rs

@@ -1,8 +1,3 @@
-// variables3.rs
-//
-// Execute `rustlings hint variables3` or use the `hint` watch subcommand for a
-// hint.
-
 fn main() {
     let x: i32;
     println!("Number {}", x);

exercises/01_variables/variables4.rs

@@ -1,8 +1,3 @@
-// variables4.rs
-//
-// Execute `rustlings hint variables4` or use the `hint` watch subcommand for a
-// hint.
-
 fn main() {
     let x = 3;
     println!("Number {}", x);

exercises/01_variables/variables5.rs

@@ -1,8 +1,3 @@
-// variables5.rs
-//
-// Execute `rustlings hint variables5` or use the `hint` watch subcommand for a
-// hint.
-
 fn main() {
     let number = "T-H-R-E-E"; // don't change this line
     println!("Spell a Number : {}", number);

exercises/01_variables/variables6.rs

@@ -1,8 +1,3 @@
-// variables6.rs
-//
-// Execute `rustlings hint variables6` or use the `hint` watch subcommand for a
-// hint.
-
 const NUMBER = 3;
 fn main() {
     println!("Number {}", NUMBER);