scene example: remove unnecessary reflect(FromWorld)

[awwsmm]

Objective

• #[reflect(FromWorld)] was added to ComponentB somewhere between v0.12.1 and v0.13.0, but it is unnecessary

Solution

• remove the unnecessary FromWorld

[awwsmm]

This is the entire diff of this example between v0.12.1 and v0.13.0

diff --git a/examples/scene/scene.rs b/examples/scene/scene.rs
index 7120fd419..ef2aef66d 100644
--- a/examples/scene/scene.rs
+++ b/examples/scene/scene.rs
@@ -34,7 +34,7 @@ struct ComponentA {
 // trait comes into play. `FromWorld` gives you access to your App's current ECS `Resources`
 // when you construct your component.
 #[derive(Component, Reflect)]
-#[reflect(Component)]
+#[reflect(Component, FromWorld)]
 struct ComponentB {
     pub value: String,
     #[reflect(skip_serializing)]
@@ -118,7 +118,8 @@ fn save_scene_system(world: &mut World) {
     scene_world.spawn(ComponentA { x: 3.0, y: 4.0 });
     scene_world.insert_resource(ResourceA { score: 1 });
 
-    // With our sample world ready to go, we can now create our scene:
+    // With our sample world ready to go, we can now create our scene using DynamicScene or DynamicSceneBuilder.
+    // For simplicity, we will create our scene using DynamicScene:
     let scene = DynamicScene::from_world(&scene_world);
 
     // Scenes can be serialized like this: