Fix formatting of Yelp .MD files

I noticed that the Yelp example + article I added earlier weren't showing up on the website, even though my pull request was merged.

Having a look at a screenshot of the preview of the MD file in GitHub, it was pretty obvious I messed something up in the creation of the file:

![yelp-md-before](https://cloud.githubusercontent.com/assets/2629322/5072067/95f80584-6e7f-11e4-9df0-3af33871a378.png)

I must apologise, as I never actually tested the articles locally (I'm on Windows). :/ I used my IDE (PhpStorm) to create the files again, instead of Notepad which I used this morning. So I think that had something to do with it too.

Anyway, I also got Ruby installed on my PC and have the styleguides project running locally. I copied one of the existing MD files and updated it with the contents from the respective Yelp example and article and it now looks like it should:

![Uploading yelp-md-after.png . . .]()

And it shows up on the website. :)

Sorry about that!