Delete all the comments by an author from all the slides in a presentation is out of date

[Delete all the comments by an author from all the slides in a presentation](https://github.com/OfficeDev/open-xml-docs/blob/main/docs/presentation/how-to-delete-all-the-comments-by-an-author-from-all-the-slides-in-a-presentatio.md#delete-all-the-comments-by-an-author-from-all-the-slides-in-a-presentation) uses the deprecated comment part and should  be updated to use modern comments. 