Update hello_terrain.adoc

Fixed broken new line and horizontal rule.

src/docs/asciidoc/jme3/beginner/hello_terrain.adoc

@@ -174,7 +174,8 @@ Here is how you create the heightmap object in your jME code:
 
 .  Create a Texture object.
 .  Load your prepared heightmap image into the texture object.
-.  Create an AbstractHeightmap object from an ImageBasedHeightMap. +It requires an image from a JME Texture.
+.  Create an AbstractHeightmap object from an ImageBasedHeightMap. +
+It requires an image from a JME Texture.
 .  Load the heightmap.
 
 [source,java]
@@ -433,6 +434,7 @@ Can you combine what you learned here and in <<jme3/beginner/hello_collision#,He
 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: