Fix issue where tapping backspace to delete a single letter also selects the previous token

[joeldrotleff]

Summary

Fixes backspace handling that selected the previous token while the text field still contained one character. Token selection now runs only after the field becomes empty.

The branch also removes the blank row below an idle token field, recalculates height when editing starts or ends, adds Swift Package Manager support for iOS 11 and later, and expands the Xcode and Swift ignore rules.

Checks

Backspace behavior works on iOS 9 and iOS 10.

Known gap

• On iOS 8, backspace on an already empty field no longer selects the previous token. The project owner confirmed this gap in review.

[joeldrotleff]

Tested and looks good on iOS 9

[rsattar]

Thank Joel!

Almost everything works here. The only issue I'm seeing is that, at least on iOS 8, you can no longer invoke delete on an empty text field to highlight the previous token (like you can in the system picker on iOS).

Looking into whether I can tweak your changes to make that work. I understand that iOS 8 is likely in low usage now, but I'd like to keep support for it, if possible.

[joeldrotleff]

@rsattar Ok deleting definitely works in iOS 10, pretty sure also in iOS 9. For my company, iOS 8 usage is down to a bit over 1% so I'm realistically not going to fix it - but I suspect conditionally going back to the previous behavior would fix the delete issue.