Using key 188 in inputKeydownMap 

Key 188 is letter "Б" of the Russian alphabet, and using it in "inputKeydownMap" in "combobox.js" makes it difficult to enter text

```
 inputKeydownMap: {
    8: 'removeLastToken', // delete
    13: 'selectOnEnter', // enter
    188: 'selectOnEnter', // comma
    27: 'hideOnEscape', // escape
    38: 'focusPrevious', // up arrow
    40: 'focusNext' // down arrow
  },
```