Improve documentation

Author: Aceeri

crates/bevy_ecs/src/removal_detection.rs

@@ -16,6 +16,8 @@ use std::{
     ops::{Deref, DerefMut},
 };
 
+/// Wrapper around a [`ManualEventReader<Entity>`] so that we
+/// can differentiate events between components.
 #[derive(Debug)]
 pub struct RemovedComponentReader<T>
 where
@@ -47,6 +49,8 @@ impl<T: Component> DerefMut for RemovedComponentReader<T> {
     }
 }
 
+/// Wrapper around a map of components to [`Events<Entity>`].
+/// So that we can find the events without naming the type directly.
 #[derive(Default, Debug)]
 pub struct RemovedComponentEvents {
     event_sets: SparseSet<ComponentId, Events<Entity>>,