"Other parameters" sections have weird formatting

The "Other parameters" heading extends across the entire text width.

See http://docs.astropy.org/en/stable/api/astropy.convolution.convolve_fft.html#astropy.convolution.convolve_fft

![otherparameters](https://cloud.githubusercontent.com/assets/38294/3780199/734731a8-198a-11e4-8900-24c74d072b8b.png)

I suspect this requires some CSS wizardry.  @kbarbary ?