Fix h3 text flowing into h2 text

As seen here: http://haacked.com/archive/2014/07/28/github-flow-aliases/ (search for GitHub Flow Aliases).
![github flow like a pro with these 13 git aliases - you_ve been haacked-1](https://cloud.githubusercontent.com/assets/23017/3722531/91345718-166a-11e4-8a25-0f0da0f4e6a3.png)

Also dropped the h3 font size a bit.