fix doctest

crates/bevy_ecs/src/world/mod.rs

@@ -1889,27 +1889,25 @@ impl World {
     ///
     ///     // Repeatedly run the update function until it requests a break.
     ///     loop {
-    ///         // Update once.
     ///         let control_flow = world.last_change_tick_scope(last_change_tick, |world| {
+    ///             // Increment the change tick so we can detect changes from the previous update.
+    ///             last_change_tick = world.change_tick();
+    ///             world.increment_change_tick();
+    ///
+    ///             // Update once.
     ///             update_fn(world)
     ///         });
     ///
     ///         // End the loop when the closure returns `ControlFlow::Break`.
     ///         if control_flow.is_break() {
     ///             break;
     ///         }
-    ///
-    ///         // Increment the change tick so the next update can detect changes from this update.
-    ///         last_change_tick = world.change_tick();
-    ///         world.increment_change_tick();
     ///     }
     /// }
     /// #
     /// # #[derive(Resource)] struct Count(u32);
     /// # let mut world = World::new();
     /// # world.insert_resource(Count(0));
-    /// # world.increment_change_tick();
-    /// #
     /// # let saved_last_tick = world.last_change_tick();
     /// # let mut num_updates = 0;
     /// # update_loop(&mut world, |world| {