Fix mIRC color override for nox

The color-number attribute needs to be quoted for webkit (no, really; verified with direct testing). Add an override for mIRC color 6 (purple) to make it easier to read. Also remove the ltype selector from the existing override, as it is entirely possible for these colors to be used in ACTIONs as well as normal PRIVMSGs.

I'd also like to clean up the inconsistent spacing in this file (it looks like it's mostly tabs with some spaces mixed in) and fix the attribute values that need quotes. If that's something people are interested in, I can have it done pretty quickly. Yay, automated tools!