Add newline to fix document markup

Fix to highlight code example.

* before
![2013-12-19 4 27 20](https://f.cloud.github.com/assets/290782/1776724/9cf10ac8-681a-11e3-9b91-e3308ad170e3.png)

* after
![2013-12-19 4 27 29](https://f.cloud.github.com/assets/290782/1776725/9cf1e920-681a-11e3-9996-6abfc265278c.png)