Update README.md

Author: ProfLander

README.md

@@ -147,7 +147,7 @@ and uses it to validate entry points at material specialization time.
 This prevents bevy from panicking when an invalid entrypoint is requested, falls back to the default shader,
 and re-specializes the material if it becomes available after a reload.
 
-Note: AssetServer gives up on trying to load an asset if it does not exist,
+**Note:** AssetServer gives up on trying to load an asset if it does not exist,
 so the `.spv` file must be compiled at least once prior to app startup in order to hot-reload successfully.
 
 ### `hot-rebuild`