docs: cleanup the explanation paragraphs at the start of each exercise.

exercises/iterators/iterators3.rs

@@ -1,10 +1,13 @@
 // iterators3.rs
-// This is a bigger exercise than most of the others! You can do it!
-// Here is your mission, should you choose to accept it:
+//
+// This is a bigger exercise than most of the others! You can do it! Here is
+// your mission, should you choose to accept it:
 // 1. Complete the divide function to get the first four tests to pass.
 // 2. Get the remaining tests to pass by completing the result_with_list and
 //    list_of_results functions.
-// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a hint.
+//
+// Execute `rustlings hint iterators3` or use the `hint` watch subcommand for a
+// hint.
 
 // I AM NOT DONE
 
@@ -26,14 +29,16 @@ pub fn divide(a: i32, b: i32) -> Result<i32, DivisionError> {
     todo!();
 }
 
-// Complete the function and return a value of the correct type so the test passes.
+// Complete the function and return a value of the correct type so the test
+// passes.
 // Desired output: Ok([1, 11, 1426, 3])
 fn result_with_list() -> () {
     let numbers = vec![27, 297, 38502, 81];
     let division_results = numbers.into_iter().map(|n| divide(n, 27));
 }
 
-// Complete the function and return a value of the correct type so the test passes.
+// Complete the function and return a value of the correct type so the test
+// passes.
 // Desired output: [Ok(1), Ok(11), Ok(1426), Ok(3)]
 fn list_of_results() -> () {
     let numbers = vec![27, 297, 38502, 81];