More descriptive output change descriptions

[amyjko]

What are you trying to do that you can't?

The aria-label descriptions of changed output currently generated by OutputDescriptions.ts:describeChangedOutput are too verbose and do not leverage any custom descriptions on a Stage, Group, or Phrase. For an extreme test case, consider the Camera stream, rendered with each pixel as a Phrase. The description of this is something to the effect of hundreds of phrases changed colors.

What is your idea?

Modify describeChangedOutput to have a behavior such as:

• If only one or outputs changed, describe what changed about it in the current locale
• If more than outputs changed, generally describe what changed about them by using the description of the Group or Stage that contains them.

There's some design work to do to figure out exactly what these templated descriptions might be, and how to express them in all supported locales, but the implementation work will likely be restricted to this one function and locales.