[Validation series] Required validation for int? property gives warnings in markup

I’ve succeeded in validating with [Required] an int property by switching it to int?.

Now I got warnings in two places in markup

…and no, the null-forgiving operator (! suffixed) does not work

oh man

Although they are working at runtime, this has dev/tester productivity significance because they clutter the markup and don’t make it readily seeable that pages or sections of pages have or don’t have issues with the bindings.