Reduce whitestroke size on markup

As per tech writer request, smaller white outlines/inlines look better.
Shrink them.

Before:
![indznwpdgaphytvd](https://f.cloud.github.com/assets/698869/676213/2865881c-d901-11e2-8d7f-2b08f3173c73.jpg)

After:
![4ekqvrcq6cny1tfp](https://f.cloud.github.com/assets/698869/676223/3d125e5c-d901-11e2-9c1b-3d5dac0bb01e.jpg)