change to xref

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

@@ -409,18 +409,14 @@ For this exercise, you can keep using the splat Material from the sample code ab
 
 === Exercise 3: Solid Terrains
 
-Can you combine what you learned here and in <<jme3/beginner/hello_collision#,Hello Collision>>, and <<jme3/advanced/terrain_collision#,make the terrain solid>>?
+Can you combine what you learned here and in xref:beginner/hello_collision.adoc[Hello Collision], and xref:ROOT:jme3/advanced/terrain_collision.adoc[make the terrain solid]?
 
 
 == Conclusion
 
 You have learned how to create terrains that are more efficient than loading one giant model. You know how to generate random or create handmade heightmaps. You can add a LOD control to render large terrains faster. You are aware that you can combine what you learned about collision detection to make the terrain solid to a physical player. You are also able to texture a terrain “like a boss using layered Materials and texture splatting. You are aware that the jMonkeyEngine SDK provides a TerrainEditor that helps with most of these manual tasks.
 
-Do you want to hear your players say '`ouch!`' when they bump into a wall or fall off a hill? Continue with learning <<jme3/beginner/hello_audio#,how to add sound>> to your game.
+*See also:*
 
-'''
-
-See also:
-
-*  <<jme3/advanced/terrain_collision#,Terrain Collision>>
-*  <<jme3/advanced/terrain.html#, Advanced Terrain>>
+*  xref:ROOT:jme3/advanced/terrain_collision.adoc[Terrain Collision]
+*  xref:ROOT:jme3/advanced/terrain.html.adoc[Advanced Terrain]