app.world access is functions now

- [9202](bevyengine/bevy#9202) changed world access to functions. [relevent line](https://github.com/bevyengine/bevy/pull/9202/files#diff-b2fba3a0c86e496085ce7f0e3f1de5960cb754c7d215ed0f087aa556e529f97fR640)
- This also surfaced [12655](bevyengine/bevy#12655) which removed `Into<AssetId<T>>` for `Handle<T>`. using a reference or .id() is the solution here.

Author: ChristopherBiscardi

src/render/mod.rs

@@ -112,10 +112,10 @@ impl Plugin for TilemapRenderingPlugin {
 
         app.add_plugins(MaterialTilemapPlugin::<StandardTilemapMaterial>::default());
 
-        app.world
+        app.world_mut()
             .resource_mut::<Assets<StandardTilemapMaterial>>()
             .insert(
-                Handle::<StandardTilemapMaterial>::default(),
+                Handle::<StandardTilemapMaterial>::default().id(),
                 StandardTilemapMaterial::default(),
             );
     }