Add Headings and First-Letter Indexing to the List of Accessibility Techniques

[judithhinlung]

VoiceOver users currently navigate through the list of accessibility techniques is by swiping left and right, which could take a long time for techniques whose first letters are further down the alphabet. This issues suggests using first-letter indexing and headings to facilitate quicker navigation.

[pauljadam]

Thank you for the suggestion! It looks like this A-Z index functionality (like Contacts.app) is not natively built into SwiftUI yet like it is with UIKit. I unsuccessfully tried to add similar functionality. I will try to come back to this issue sometime in the future when SwiftUI adds a native a-z index functionality like UIKit has with the Contacts app.