website: change color of text on selection

Total nitpick but this was bothering me.

Changes selection from the docs from this:

![screen shot 2013-06-29 at 9 24 55 pm](https://f.cloud.github.com/assets/846194/726385/063f752e-e0f2-11e2-83bd-10c0e1f6baac.png)

To this:

![screen shot 2013-06-29 at 9 24 37 pm](https://f.cloud.github.com/assets/846194/726384/04fe520c-e0f2-11e2-9488-c7cc820d3f35.png)