Add ref structs support

[vvdev]

Hello.

Currently when ref struct type is passed, it crashes with "ArgumentException: GenericArguments[0], 'SomeRefStructType, on 'ObjectLayoutInspector.TypeInspector+SizeComputer`1[T]' violates the constraint of type 'T'."

I have seen old bug about ref structs inspection issues, but maybe with use of NET9+ allows ref struct constraint plus some (hopefully) easy related fixes it could work now?
I use you library regularly, but really missing ref struct inspection possibility.

Thanks.

[SergeyTeplyakov]

Good idea! Will add!