Clean up and unify exercises

exercises/17_tests/tests1.rs

@@ -1,14 +1,9 @@
-// tests1.rs
-//
 // Tests are important to ensure that your code does what you think it should
 // do. Tests can be run on this file with the following command: rustlings run
 // tests1
 //
 // This test has a problem with it -- make the test compile! Make the test pass!
 // Make the test fail!
-//
-// Execute `rustlings hint tests1` or use the `hint` watch subcommand for a
-// hint.
 
 fn main() {
     // You can optionally experiment here.

exercises/17_tests/tests2.rs

@@ -1,10 +1,5 @@
-// tests2.rs
-//
 // This test has a problem with it -- make the test compile! Make the test pass!
 // Make the test fail!
-//
-// Execute `rustlings hint tests2` or use the `hint` watch subcommand for a
-// hint.
 
 fn main() {
     // You can optionally experiment here.

exercises/17_tests/tests3.rs

@@ -1,11 +1,6 @@
-// tests3.rs
-//
 // This test isn't testing our function -- make it do that in such a way that
 // the test passes. Then write a second test that tests whether we get the
 // result we expect to get when we call `is_even(5)`.
-//
-// Execute `rustlings hint tests3` or use the `hint` watch subcommand for a
-// hint.
 
 pub fn is_even(num: i32) -> bool {
     num % 2 == 0

exercises/17_tests/tests4.rs

@@ -1,9 +1,4 @@
-// tests4.rs
-//
 // Make sure that we're testing for the correct conditions!
-//
-// Execute `rustlings hint tests4` or use the `hint` watch subcommand for a
-// hint.
 
 struct Rectangle {
     width: i32,