Update walking_character.adoc

Fixed broken link.

src/docs/asciidoc/jme3/advanced/walking_character.adoc

@@ -8,7 +8,7 @@
 ifdef::env-github,env-browser[:outfilesuffix: .adoc]
 
 
-In the <<jme3/beginner/hello_collision#,Hello Collision>> tutorial and the link:http://code.google.com/p/jmonkeyengine/source/browse/trunk/engine/src/test/jme3test/bullet/TestQ3.java[TestQ3.java] code sample you have seen how to create collidable landscapes and walk around in a first-person perspective. The first-person camera is enclosed by a collision shape and is steered by the BetterCharacterControl. 
+In the <<jme3/beginner/hello_collision#,Hello Collision>> tutorial and the link:https://github.com/jMonkeyEngine/jmonkeyengine/blob/master/jme3-examples/src/main/java/jme3test/bullet/TestQ3.java[TestQ3.java] code sample you have seen how to create collidable landscapes and walk around in a first-person perspective. The first-person camera is enclosed by a collision shape and is steered by the BetterCharacterControl. 
 
 Other games however require a third-person perspective of the character: In these cases you use a CharacterControl on a Spatial. This example also shows how to set up custom navigation controls, so you can press WASD to make the third-person character walk; and how to implement dragging the mouse to rotate.