Clarify Texture Atlas rework migration guide

content/learn/migration-guides/0.12-to-0.13.md

@@ -878,6 +878,20 @@ Renamed `PbrInput::occlusion` to `diffuse_occlusion`, and added `specular_occlus
     <div class="migration-guide-area-tag">Rendering</div>
 </div>
 
+The `TextureAtlas` asset that previously contained both the atlas layout and image handle was renamed to `TextureAtlasLayout` with the image handle portion moved to a separate `Handle<Image>` available from `SpriteSheetBundle::texture` or `AtlasImageBundle::image`.
+
+`TextureAtlasSprite` was removed and replaced by a new component, `TextureAtlas`, which now holds the atlas index. The `Sprite` component can be used for `flip_x`, `flip_y`, `custom_size`, `anchor`, and `color`.
+
+`SpriteSheetBundle` now uses a `Sprite` instead of a `TextureAtlasSprite` component and a `TextureAtlas` component instead of a `Handle<TextureAtlaslayout>`.
+
+`DynamicTextureAtlasBuilder::add_texture` takes an additional `&Handle<Image>` parameter.
+
+`TextureAtlasLayout::from_grid` no longer takes a `Handle<Image>` parameter.
+
+`TextureAtlasBuilder::finish` now returns a `Result<(TextureAtlasLayout, Image), TextureAtlasBuilderError>`.
+
+`UiTextureAtlasImage` was removed. The `AtlasImageBundle` is now identical to `ImageBundle` with an additional `TextureAtlas`.
+
 - Sprites
 
 ```diff
@@ -894,12 +908,14 @@ fn my_system(
     commands.spawn(SpriteSheetBundle {
 -      sprite: TextureAtlasSprite::new(0),
 -      texture_atlas: atlas_handle,
+       // the new sprite initialization is covered by the `..default()` expression; however, it is added to showcase migration
++      sprite: Sprite::default()
 +      atlas: TextureAtlas {
 +         layout: layout_handle,
 +         index: 0
 +      },
 +      texture: texture_handle,
-       ..Default::default()
+       ..default()
      });
 }
 ```
@@ -933,11 +949,38 @@ fn my_system(
 +           flip_x: false,
 +           flip_y: false,
 +       },
-       ..Default::default()
+       ..default()
      });
 }
 ```
 
+- Queries (taken from the [sprite sheet example](https://bevyengine.org/examples/2D%20Rendering/sprite-sheet/))
+
+```diff
+fn animate_sprite(
+    time: Res<Time>,
+    mut query: Query<(
+        &AnimationIndices,
+        &mut AnimationTimer,
+-       &mut TextureAtlasSprite)>,
++       &mut TextureAtlas)>,
+) {
+-   for (indices, mut timer, mut sprite) in &mut query {
++   for (indices, mut timer, mut atlas) in &mut query {
+        timer.tick(time.delta());
+        if timer.just_finished() {
+-           sprite.index = if sprite.index == indices.last {
++           atlas.index = if atlas.index == indices.last {
+                indices.first
+            } else {
+-               sprite.index + 1
++               atlas.index + 1
+            };
+        }
+    }
+}
+```
+
 ### [Exposure settings (adopted)](https://github.com/bevyengine/bevy/pull/11347)
 
 <div class="migration-guide-area-tags">