code: function getHeadingEl(e, isFake) {
      let headingEl = e.target;
      const headingClass = prefix(isFake, 'tabs__item');
      while (!headingEl.classList.contains(headingClass)) {
          headingEl = headingEl.parentNode;
      }
      return headingEl;
  }
docs: Get heading element from event
  @param {Event} e
  @param {Boolean} isFake - If the tabs are fake