wrapGroups(node, pos, len, eachCb) {
    node = this.wrapRangeInTextNode(node, pos, pos + len);
    eachCb(node.previousSibling);
    return node;
  }
@param {HTMLElement} node - The text node where the match occurs
@param {number} pos - The current position of the match within the node
@param {number} len - The length of the current match within the node
@param {Mark~wrapMatchesEachCallback} eachCb