getContextualVendorSpecificPseudoElements(node) {
    function walkDown(s, n) {
      for (const child of n.getChildren()) {
        if (child.type === NodeType.PseudoSelector) {
          const pseudoElement = child.getChildren()[0]?.getText();
          if (pseudoElement) {
            s.add(pseudoElement);
          }
        }
        walkDown(s, child);
      }
    }
    function walkUp(s, n) {
      if (n.type === NodeType.Ruleset) {
        for (const selector of n.getSelectors().getChildren()) {
          walkDown(s, selector);
        }
      }
      return n.parent ? walkUp(s, n.parent) : void 0;
    }
    const result = /* @__PURE__ */ new Set();
    walkUp(result, node);
    return Array.from(result);
  }
Walks up the syntax tree (starting from given `node`) and captures vendor
specific pseudo-element selectors.
@returns An array of vendor specific pseudo-elements; or empty if none
was found.