Method insertBefore

packages/types/src/shell/model/node.ts:371–371

* 在指定位置之前插入一个节点 * insert a node befor current node * @param node * @param ref * @param useMutator

(
      node: Node,
      ref?: Node | undefined,
      useMutator?: boolean,
    )

   * @param useMutator
   */
  insertBefore(
      node: Node,
      ref?: Node | undefined,
      useMutator?: boolean,