Mentioned jme3-plugins to load xml model (#141)

docs/modules/tutorials/pages/beginner/hello_asset.adoc

@@ -168,7 +168,7 @@ Clear existing text in the guiNode by detaching all its children.
 
 === Loading a Model
 
-Export your 3D model in a <<ROOT:getting-started/features.adoc#supported-external-file-types,Supported External File Type>> (.mesh.xml, .scene, .material, .skeleton.xml, .gltf) and place it in a subdirectory of `assets/Models/`. The following code sample goes into the `simpleInitApp()` method.
+Export your 3D model in a <<ROOT:getting-started/features.adoc#supported-external-file-types,Supported External File Type>> (.mesh.xml, .scene, .material, .skeleton.xml, .gltf) and place it in a subdirectory of `assets/Models/`. The following code sample goes into the `simpleInitApp()` method. Note that "jme3-plugins" library is needed to load these file types.
 
 [source,java]
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