Event mutator release notes (#1759)

release-content/0.15/release-notes/13818_Created_an_EventMutator_for_when_you_want_to_mutate_an_eve.md

@@ -2,3 +2,28 @@
 <!-- https://github.com/bevyengine/bevy/pull/13818 -->
 
 <!-- TODO -->
+
+When working with complex event-driven logic, you may find that you want to conditionally modify events without changing their type or re-emitting them.
+While this has always been possible, it was quite onerous:
+
+```rust
+// We need to manually track which events this system has read
+// using a system-local `EventCursor`, previously called `ManualEventReader`.
+fn mutate_events(mut events: ResMut<Events<MyEvent>>, mut local_cursor: Local<EventCursor<MyEvent>>){    
+    for event in local_cursor.read_mut(&mut *events){
+        event.mutate();
+    }
+}
+```
+
+Now, you can simply use the new [`EventMutator`] system param, which keeps track of this bookkeeping for you.
+
+```rust
+fn mutate_events(mut event_mutator: EventMutator<MyEvent>>){    
+    for event in event_mutator.read(){
+        event.mutate();
+    }
+}
+```
+
+[`EventMutator`]: https://docs.rs/bevy/0.15/bevy/ecs/event/struct.EventMutator.html

release-content/0.15/release-notes/_release-notes.toml

@@ -20,7 +20,7 @@ prs = [14071]
 file_name = "14071_Uniform_mesh_sampling.md"
 
 [[release_notes]]
-title = "Created an EventMutator for when you want to mutate an event before reading"
+title = "`EventMutator`"
 authors = ["@BobG1983"]
 contributors = ["@atornity", "@alice-i-cecile"]
 prs = [13818]
@@ -453,8 +453,7 @@ file_name = "15800_Add_mesh_picking_backend_and_MeshRayCast_system_parameter.md"
 
 [[release_notes]]
 title = "Required Components"
-authors = ["@cart",]
+authors = ["@cart"]
 contributors = ["@alice-i-cecile", "@killercup", "@BD103"]
 prs = [14791]
 file_name = "14791_Required_Components.md"
-