Update app.rs

Author: maniwani

crates/bevy_app/src/app.rs

@@ -13,6 +13,7 @@ use bevy_ecs::{
 use bevy_utils::{tracing::debug, HashMap};
 use std::fmt::Debug;
 
+// temporary
 #[cfg(feature = "trace")]
 use bevy_utils::tracing::info_span;
 bevy_utils::define_label!(