docs: function(method, note) {
      if (!this.app.enabled('track changes')) {
        return;
      }
      var state = this.omit('history');
      state.tracked = {location: method, note: note};
      state.inspect = function() {
        return '<' + method + ': ' + note + '>';
      };
      this.options.history = this.options.history || [];
      this.options.history.push(state);
      return this;
    }