[css-counter-styles] dynamic setting of name

http://dev.w3.org/csswg/css-counter-styles/#the-csscounterstylerule-interface
says:

2. If the returned value is an <custom-ident>, and the <custom-ident>’s
representation is not an ASCII case-insensitive match for "decimal" or
"none", replace the associated rule’s name with the <custom-ident>'s
representation.

I think it should also mention that the names defined in the spec should be
lower-cased before the replacement.

- Xidorn