misunderstand the implements verb (#18)

* Update 08_from.md

* test

* Update exercises/04_traits/08_from/src/lib.rs

---------

Co-authored-by: datewu <hihahajun@gmail.com>
Co-authored-by: Luca Palmieri <20745048+LukeMathWalker@users.noreply.github.com>

exercises/04_traits/08_from/src/lib.rs

@@ -1,4 +1,4 @@
-// TODO: Implement the `From` trait for the `u32` type to make `example` compile.
+// TODO: Implement the `From` trait for the `WrappingU32` type to make `example` compile.
 
 pub struct WrappingU32 {
     value: u32,