Update README.md

Line break with a bullet list for consistency.

Author: hexbreak

exercises/03-flip_list/README.md

@@ -16,5 +16,5 @@ Final list:    [60, 32, 5 , 23, 87, 67, 45]
 ```
 
 
-💡Hint
-You should loop the entire list, and push all the items (as you go) into a new list.
+💡Hint:
+- You should loop the entire list, and push all the items (as you go) into a new list.