docs: function () {
          if (!this._active) {
              return
          }
          const editor = this.editor
          const $selectionELem = editor.selection.getSelectionContainerElem()
          if (!$selectionELem) {
              return
          }
          const selectionText = editor.selection.getSelectionText()
          editor.cmd.do('insertHTML', '<span>' + selectionText + '</span>')
      }