remove reference to earth

Author: nicopap

examples/3d/parallax_mapping.rs

@@ -322,8 +322,7 @@ fn setup(
     );
 }
 
-/// Store handle of the earth normal to later modify its format
-/// in [`update_normal`].
+/// Store handle of the normal to later modify its format in [`update_normal`].
 #[derive(Resource)]
 struct Normal(Option<Handle<Image>>);