Issue #747

Need to use Coordinator conforming to UITextViewDelegate to apply changes back to Binding

import SwiftUI
import UIKit

struct MyTextView: UIViewRepresentable {
    @Binding
    var text: String

    final class Coordinator: NSObject, UITextViewDelegate {
        let parent: MyTextView

        init(parent: MyTextView) {
            self.parent = parent
        }

        func textViewDidChange(_ textView: UITextView) {
            if textView.text != parent.text {
                parent.text = textView.text
            }
        }
    }

    func makeCoordinator() -> Coordinator {
        Coordinator(parent: self)
    }

    func makeUIView(context: Context) -> UITextView {
        let view = UITextView()
        view.isScrollEnabled = true
        view.isEditable = true
        view.isUserInteractionEnabled = true
        view.font = UIFont.preferredFont(forTextStyle: .body)
        view.delegate = context.coordinator
        return view
    }

    func updateUIView(_ uiView: UITextView, context: Context) {
        uiView.text = text
    }
}