chore(css): Update group field for css selectors

[skyclouds2001]

Description

to make the group field really represents which module the feature is defined

Motivation

Additional details

Related issues and pull requests

[bsmth]

Thanks a lot. In general, this is technically correct, so I would be curious to get another opinion again on whether:

make the group field really represents which module the feature is defined

is what consumers expect as opposed to these returned when someone is looking for a list of pseudo-classes or pseudo-elements. "Defined in" versus "can be classed as" is a good distinction to double-check.