[Feat] Find variables inside other selectors

[scriptcoded]

Is your feature request related to a problem? Please describe.
Hey! In our project we have some variables which are scoped using attributes. For example:

[data-some-setting] {
  --size: 12px;
}

There doesn't seem to be a way of getting the extension to identify these variables. I thought this would work with themes but unfortunately those only seem to work with classes.

Describe the solution you'd like
I see two potential solutions, maybe both could co-exist.

1. Make it so that you can disable checking for selectors and just grabbing all variables.
2. Make it so that the theme setting uses selectors and not class names. So ['.dark'] instead of ['dark'].

Describe alternatives you've considered
I think both alternatives mentioned would be feasible. Can't think of anything else unfortunately.

Additional context
Add any other context or screenshots about the feature request here.