fix(errors3): Update hint

Closes #185.

Author: marisa

exercises/error_handling/errors3.rs

@@ -1,8 +1,7 @@
 // errors3.rs
 // This is a program that is trying to use a completed version of the
-// `total_cost` function from the previous exercise. It's not working though--
-// we can't use the `?` operator in the `main()` function! Why not?
-// What should we do instead? Scroll for hints!
+// `total_cost` function from the previous exercise. It's not working though!
+// Why not? What should we do to fix it? Scroll for hints!
 
 use std::num::ParseIntError;
 
@@ -45,18 +44,4 @@ pub fn total_cost(item_quantity: &str) -> Result<i32, ParseIntError> {
 
 
 
-// Since the `?` operator returns an `Err` early if the thing it's trying to
-// do fails, you can only use the `?` operator in functions that have a
-// `Result` as their return type.
-
-// Hence the error that you get if you run this code is:
-
-// ```
-// error[E0277]: the `?` operator can only be used in a function that returns `Result` (or another type that implements `std::ops::Try`)
-// ```
-
-// So we have to use another way of handling a `Result` within `main`.
-
-// Decide what we should do if `pretend_user_input` has a string value that does
-// not parse to an integer, and implement that instead of using the `?`
-// operator.
+// If other functions can return a `Result`, why shouldn't `main`?