[css-counter-styles] Name conflict in CSSCounterStyleRule IDL

I've flattened the descriptors for @counter-style into the
CSSCounterStyleRule interface, but that produces a naming conflict - I
have a 'type' descriptor, but CSSRule also defines a 'type' attribute
(for the type of the rule).

Opinions on what the attribute corresponding to the 'type' descriptor
should be named? Should I rename the descriptor itself to avoid
collisions, so that I can maintain a 1-1 relationship between the
descriptors and the IDL?

~TJ