Changed assetmanager topic to reflect only use the subfolders of the assets directory to store assets.

src/docs/asciidoc/jme3/beginner/hello_asset.adoc

@@ -104,7 +104,7 @@ Build and run the code sample. You should see a green Ninja with a colorful teap
 The AssetManager can load files from:
 
 *  The current classpath (the top level of your project directory).
-*  The `assets` directory of your project.
+*  The sub-folders of the `assets` directory of your project.
 *  Optionally, custom paths that you register.
 
 The following is the recommended directory structure for storing assets in your project directoy: