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

exercises/conversions/from_into.rs

@@ -1,7 +1,11 @@
-// The From trait is used for value-to-value conversions.
-// If From is implemented correctly for a type, the Into trait should work conversely.
-// You can read more about it at https://doc.rust-lang.org/std/convert/trait.From.html
-// Execute `rustlings hint from_into` or use the `hint` watch subcommand for a hint.
+// from_into.rs
+//
+// The From trait is used for value-to-value conversions. If From is implemented
+// correctly for a type, the Into trait should work conversely. You can read
+// more about it at https://doc.rust-lang.org/std/convert/trait.From.html
+//
+// Execute `rustlings hint from_into` or use the `hint` watch subcommand for a
+// hint.
 
 #[derive(Debug)]
 struct Person {
@@ -20,20 +24,21 @@ impl Default for Person {
     }
 }
 
-// Your task is to complete this implementation
-// in order for the line `let p = Person::from("Mark,20")` to compile
-// Please note that you'll need to parse the age component into a `usize`
-// with something like `"4".parse::<usize>()`. The outcome of this needs to
-// be handled appropriately.
+// Your task is to complete this implementation in order for the line `let p =
+// Person::from("Mark,20")` to compile Please note that you'll need to parse the
+// age component into a `usize` with something like `"4".parse::<usize>()`. The
+// outcome of this needs to be handled appropriately.
 //
 // Steps:
-// 1. If the length of the provided string is 0, then return the default of Person
-// 2. Split the given string on the commas present in it
-// 3. Extract the first element from the split operation and use it as the name
-// 4. If the name is empty, then return the default of Person
-// 5. Extract the other element from the split operation and parse it into a `usize` as the age
-// If while parsing the age, something goes wrong, then return the default of Person
-// Otherwise, then return an instantiated Person object with the results
+// 1. If the length of the provided string is 0, then return the default of
+//    Person.
+// 2. Split the given string on the commas present in it.
+// 3. Extract the first element from the split operation and use it as the name.
+// 4. If the name is empty, then return the default of Person.
+// 5. Extract the other element from the split operation and parse it into a
+//    `usize` as the age.
+// If while parsing the age, something goes wrong, then return the default of
+// Person Otherwise, then return an instantiated Person object with the results
 
 // I AM NOT DONE
 
@@ -77,7 +82,8 @@ mod tests {
     }
     #[test]
     fn test_bad_age() {
-        // Test that "Mark,twenty" will return the default person due to an error in parsing age
+        // Test that "Mark,twenty" will return the default person due to an
+        // error in parsing age
         let p = Person::from("Mark,twenty");
         assert_eq!(p.name, "John");
         assert_eq!(p.age, 30);