Fix CSS selector splitting

[ilanus]

Closes #22

Fixes split for CSS selectors.

splitSelectors(".a, .b")
// [ '.a', '.b' ]

splitSelectors(".a")
// [ '.a' ]

splitSelectors("::slotted(:is(button, a):active), ::slotted(:is(button, a):hover)")
// [
//   '::slotted(:is(button, a):active)',
//   '::slotted(:is(button, a):hover)'
// ]

splitSelectors("::slotted(:is(button, a):active)")
// [ '::slotted(:is(button, a):active)' ]

splitSelectors(":host([type='secondary']) ::slotted(:is(button, a)), :host([type='primary']) ::slotted(:is(button, a):active)")
// [
//   ":host([type='secondary']) ::slotted(:is(button, a))",
//   ":host([type='primary']) ::slotted(:is(button, a):active)"
// ]

splitSelectors(":host([outline]) ::slotted(:is(button, a):focus-within:focus-visible:not(:active))")
// [
//   ':host([outline]) ::slotted(:is(button, a):focus-within:focus-visible:not(:active))'
// ]

[github-actions]

🚀 PR was released in v1.14.0 🚀