code: function parseSelector(rawSelector) {
      const parsedSelector = tryParseSelector(rawSelector)
  
      return {
          rawSelector,
          isExit: rawSelector.endsWith(":exit"),
          parsedSelector,
      }
  }
docs: Parses a raw selector string, and returns the parsed selector along with specificity and type information.
  @param {string} rawSelector A raw AST selector
  @returns {ASTSelector} A selector descriptor