Update hello_simpleapplication.adoc

Fixed broken horizontal rule.

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

@@ -238,6 +238,7 @@ When developing a game application, you want to:
 The now following tutorials teach how you accomplish these tasks with the jMonkeyEngine 3.
 
 Continue with the <<jme3/beginner/hello_node#,Hello Node>> tutorial, where you learn more details about how to initialize the game world, also known as the scene graph.
+
 '''
 
 See also: