In other words, this is a flattened alternative to UnwrapOr(T).
var or = Some(12).Or(Some(13));
Assert.Equal(Some(12), or);
or = Some(12).Or(None<int>());
Assert.Equal(Some(12), or);
or = None<int>().Or(Some(13));
Assert.Equal(Some(13), or);
or = None<int>().Or(None<bool>());
Assert.True(or.IsNone);
public Opt<T> Or(
Opt<T> other
)