Removed erroneous space in code example.

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

@@ -192,7 +192,6 @@ public class HelloTerrainCollision extends SimpleApplication
       if (value) { down = true; } else { down = false; }
     } else if (binding.equals("Jump")) {
       player.jump(new Vector3f(0,20f,0));
-
     }
   }