Implement the UIResponderStandardEditActions protocol, move the
corresponding API from UIResponder there, and make sure UIResponder implements
the new UIResponderStandardEditActions protocol (which should make this move a
non-breaking change, since the protocol is inlined in UIResponder).
* Use the native `NSStringFrom*` API so we can, eventually, use the
native code to parse them from `NSString` and also ensure increased
compatibility with any code that expects the native string representation
* Add unit tests for `ToString` methods
Also use [`System.HashCode`](https://docs.microsoft.com/en-us/dotnet/api/system.hashcode?view=net-6.0) to generate the hash code
Once upon a long time ago we decided to mark the properties in the
UITextInputTraits protocol as required in our API definition, because that way
we'd inline these properties in any class that implemented the
UITextInputTraits protocol, which made calling these properties much easier.
At a later point, we implemented better support for protocols, and now we
automatically generate extension methods for such properties (a corresponding
Get/Set method for the get/set property accessors), so we don't need these
inlined properties anymore.
However, removing them would be a breaking change, so we were stuck with these
redundant inlined properties, until .NET came along.
Ref: 0e80570863
Fixes https://github.com/xamarin/xamarin-macios/issues/5831.
Rolf Bjarne Kvinge
Sebastien Pouliot