*Issue #, if available:*

*Description of changes:*


By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Pull Request Checklist:
* [ ] No backwards incompatible changes were made to Ace's public interface which is defined through the main typings file (`ace.d.ts`) and its references:
    * https://github.com/ajaxorg/ace/blob/master/ace.d.ts 
    * https://github.com/ajaxorg/ace/blob/master/ace-modes.d.ts 
    * https://github.com/ajaxorg/ace/blob/master/ace-extensions.d.ts

