Clean up and unify exercises

exercises/23_conversions/as_ref_mut.rs

@@ -1,11 +1,6 @@
-// as_ref_mut.rs
-//
 // AsRef and AsMut allow for cheap reference-to-reference conversions. Read more
 // about them at https://doc.rust-lang.org/std/convert/trait.AsRef.html and
 // https://doc.rust-lang.org/std/convert/trait.AsMut.html, respectively.
-//
-// Execute `rustlings hint as_ref_mut` or use the `hint` watch subcommand for a
-// hint.
 
 // Obtain the number of bytes (not characters) in the given argument.
 // TODO: Add the AsRef trait appropriately as a trait bound.

exercises/23_conversions/from_into.rs

@@ -1,11 +1,6 @@
-// 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 {
@@ -24,7 +19,6 @@ impl Default for Person {
     }
 }
 
-
 // Your task is to complete this implementation in order for the line `let p1 =
 // 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

exercises/23_conversions/from_str.rs

@@ -1,13 +1,8 @@
-// from_str.rs
-//
 // This is similar to from_into.rs, but this time we'll implement `FromStr` and
 // return errors instead of falling back to a default value. Additionally, upon
 // implementing FromStr, you can use the `parse` method on strings to generate
 // an object of the implementor type. You can read more about it at
 // https://doc.rust-lang.org/std/str/trait.FromStr.html
-//
-// Execute `rustlings hint from_str` or use the `hint` watch subcommand for a
-// hint.
 
 use std::num::ParseIntError;
 use std::str::FromStr;

exercises/23_conversions/try_from_into.rs

@@ -1,13 +1,8 @@
-// try_from_into.rs
-//
 // TryFrom is a simple and safe type conversion that may fail in a controlled
 // way under some circumstances. Basically, this is the same as From. The main
 // difference is that this should return a Result type instead of the target
 // type itself. You can read more about it at
 // https://doc.rust-lang.org/std/convert/trait.TryFrom.html
-//
-// Execute `rustlings hint try_from_into` or use the `hint` watch subcommand for
-// a hint.
 
 use std::convert::{TryFrom, TryInto};
 

exercises/23_conversions/using_as.rs

@@ -1,14 +1,9 @@
-// using_as.rs
-//
 // Type casting in Rust is done via the usage of the `as` operator. Please note
 // that the `as` operator is not only used when type casting. It also helps with
 // renaming imports.
 //
 // The goal is to make sure that the division does not fail to compile and
 // returns the proper type.
-//
-// Execute `rustlings hint using_as` or use the `hint` watch subcommand for a
-// hint.
 
 fn average(values: &[f64]) -> f64 {
     let total = values.iter().sum::<f64>();