rs in codeblocks

Author: ChristopherBiscardi

release-content/migration-guides/gltf_pbr.md

@@ -7,14 +7,14 @@ Previously, `bevy_gltf` depended on `bevy_pbr`. This meant scene definition was
 
 In 0.18, loading a material sub-asset would return a `Handle<StandardMaterial>`.
 
-```
+```rs
 let handle: Handle<StandardMaterial> = asset_server.load("models/animated/Fox.glb#Material0");
 ```
 
 In 0.19, loading a material sub-asset loads a `GltfMaterial` to accurately represent the data in the glTF file.
 To load the `StandardMaterial`, use the `/std` suffix when the `bevy_pbr` feature is turned on (the feature is on by default).
 
-```
+```rs
 let handle: Handle<GltfMaterial> = asset_server.load("models/animated/Fox.glb#Material0");
 let handle_std: Handle<StandardMaterial> = asset_server.load("models/animated/Fox.glb#Material0/std");
 ```