Update documentation.md

Documentation/GitHub/documentation.md

@@ -3,5 +3,5 @@
 Banshee comes with extensive documentation for both its native and managed code. On top of the API documentation that covers both engine internals and user-facing code, a variety of manuals are provided to get your started.
 
 Visit the documentation below:
- - [Native](http://docs.banshee3d.com/Native/index.html)
- - [Managed](http://docs.banshee3d.com/Managed/index.html)
+ - [Native (link dead)](https://github.com/larioteo/BansheeEngine)
+ - [Managed (link dead)](https://github.com/larioteo/BansheeEngine)