fix(enums) make enum variants more consistent

closes #1545

exercises/08_enums/enums2.rs

@@ -10,6 +10,12 @@ enum Message {
     // TODO: define the different variants used below
 }
 
+#[derive(Debug)]
+struct Point {
+    x: u8,
+    y: u8,
+}
+
 impl Message {
     fn call(&self) {
         println!("{:?}", self);
@@ -18,7 +24,8 @@ impl Message {
 
 fn main() {
     let messages = [
-        Message::Move { x: 10, y: 30 },
+        Message::Resize { w: 10, h: 30 },
+        Message::Move(Point { x: 10, y: 15 }),
         Message::Echo(String::from("hello world")),
         Message::ChangeColor(200, 255, 255),
         Message::Quit,