Enforce Constructor Call or Add Nullable Returns

[AeonSake]

Is your feature request related to a problem? Please describe.
Currently, the IDeserializer.Deserialize<T> methods return null if the parsed string is empty (or whitespaces). However, because the interface description declares the return type as T and not T? it is not immediately obvious that null can even be a valid return value.

Describe the solution you'd like
I would like the deserializer to always enforce the type construction (optionally via a DeserializerBuilder option like WithEnforceConstructorCall() ?), or change the interface return type to T? to make it clear to the user, that null is a possibility.

Describe alternatives you've considered
Override/ignore compiler info/warning and do a null-check on the returned instance regardless.

Additional context
There may be built-in deserializer options I did not see and this might also be possible with custom type converters, object factories, etc. If that is the case, please let me know.

[EdwardCooke]

Can you not do something like this deserialize.Deserialize<SomeclassName?>(yamltext);

Or are you saying that you would just expect the interface to already have the nullable attribute by default? I think that could be a breaking change, albeit just compiler warnings but it would be annoying for existing consumers to suddenly need nullable checks or directives to get rid of them.