Update beginner.adoc

Fixed broken horizontal rule.
fixed broken link to helloworld.

src/docs/asciidoc/jme3/beginner.adoc

@@ -22,7 +22,8 @@ ifdef::env-github,env-browser[:outfilesuffix: .adoc]
 .  <<jme3/beginner/hello_physics#,Hello Physics>>
 .  <<jme3/beginner/hellovector#,Hello Vector3f>>
 
-Get the source code at link:http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/helloworld/[jme3/src/test/jme3test/helloworld/].
+Get the source code at link:https://github.com/jMonkeyEngine/jmonkeyengine/tree/master/jme3-examples/src/main/java/jme3test/helloworld[jme3-examples/src/main/java/jme3test/helloworld/].
+
 '''
 
 <<jme3#,Back to Documentation>>