[src] view shows lines first and then the code.

Clicking on the [src] link for any repo shows you first the line numbers and then the source code.

For example here: https://docs.rs/spirv-reflect/0.1.2/src/spirv_reflect/lib.rs.html#1-601


I get this on Firefox 63.0.3:

![image](https://user-images.githubusercontent.com/5849037/48805811-4e141a00-ed10-11e8-8d8e-f173e5dfa148.png)


