Fix div overflow on long code samples

I noticed a couple of places where code examples were overflowing. I've updated the markup here to flow to the next line, as is currently done for the bundle install documentation. Could also add an overflow-x style to pre elements, but it looks like existing preference is to have code sample split to additional lines. Thanks!

![ruby_version](https://cloud.githubusercontent.com/assets/1431823/4894199/6e1a69b4-63ce-11e4-9cdb-8ba9e8f05071.png)
![bundle_package](https://cloud.githubusercontent.com/assets/1431823/4894200/6e20bec2-63ce-11e4-89d4-56325d020fb7.png)