code: function _handleChange(event, editor, changeList) {
          if (lastChar && (lastChar === '(' || lastChar === ',') && editor === keyDownEditor) {
              keyDownEditor = null;
              popUpHint(editor);
          }
      }
docs: Start a new implicit hinting session, or update the existing hint list.
  Called by the editor after handleKeyEvent, which is responsible for setting
  the lastChar.
  
  @param {Event} event
  @param {Editor} editor
  @param {{from: Pos, to: Pos, text: Array, origin: string}} changeList