chore: Alter whitespace for consistency

* Add newline after "I AM DONE" in exercises for consistency
* Remove trailing whitespace from exercises

exercises/generics/generics2.rs

@@ -2,6 +2,7 @@
 // Rewrite it using generics so that it supports wrapping ANY type.
 
 // I AM NOT DONE
+
 struct Wrapper {
     value: u32
 }
@@ -18,11 +19,11 @@ mod tests {
 
     #[test]
     fn store_u32_in_wrapper() {
-        assert_eq!(Wrapper::new(42).value,  42);
+        assert_eq!(Wrapper::new(42).value, 42);
     }
 
     #[test]
     fn store_str_in_wrapper() {
         assert_eq!(Wrapper::new("Foo").value, "Foo");
     }
-}
+}