VoiceOver for macOS: Make toggle button rendering consistent with VO iOS where both pressed and not pressed states are conveyed (Track Apple rdar://100389758)

[mcking65]

From #784 where @cookiecrook wrote:

          >> Make VoiceOver's rendering of toggle buttons consistent with their treatment in iOS Safari, where VoiceOver communicates both states.

This is a reasonable request that I will discuss with the Mac and iOS teams. Thanks.

For closure, the Apple-internal tracking numbers are rdar://100389758 (for Mac) and rdar://100389766 (for iOS). Those teams will discuss potentially converging on either the Mac or iOS behavior, or some variant in between. I am not able to predict a timeline for that discussion.

Originally posted by @cookiecrook in #784 (comment)