code: function(yasqe, data, completion) {
    if (completion.text != yasqe.getTokenAt(yasqe.getCursor()).string) {
      yasqe.replaceRange(completion.text, data.from, data.to);
    }
  }
docs: function which fires after the user selects a completion. this function checks whether we actually need to store this one (if completion is same as current token, don't do anything)