HighlightByCategoryEvent for added and removed Categories in ICategorizableThings

[lxatstariongroup]

Prerequisites

• [x] I have written a descriptive issue title
• [x] I have verified that I am running the latest version of the COMET-IME
• [x] I have searched open and closed issues to ensure it has not already been reported

Description

RowViewModelBase has a TODO item that states:

// TODO: if this is indeed a categorizable thing we also have to listen to changes on added/removed categories. Need to figure out how to do this best // as the list of Categories is not reactive. Currently you will need to close and open the view after applying a category to make // highlighting work.

This should be fixed.

[MartinFijneman]

verified with 9.2.0-RC6

tested with categories added and removed from ED and/or element usages, and then highlighting > highlight is working/reacting as expected