Thanks to @Akazm for making this support iOS 13, macOS 10.15, watchOS 6, and tvOS 13.

Previously only user side changes to the text field's contents were synced back to the number property. Now you can programmatically set the NumericTextModifier.number and the text field will update.

Refactored NumericTextField's core logic into NumericTextModifier so you have more flexibility in how you use it.