add Scalar.scalar (#336)

* add Scalar.scalar

* fixup

Author: MarcoGorelli

spec/API_specification/dataframe_api/scalar_object.py

@@ -1,6 +1,6 @@
 from __future__ import annotations
 
-from typing import TYPE_CHECKING, Protocol
+from typing import TYPE_CHECKING, Any, Protocol
 
 if TYPE_CHECKING:
     from typing_extensions import Self
@@ -40,6 +40,11 @@ def __scalar_namespace__(self) -> Namespace:
         """
         ...
 
+    @property
+    def scalar(self) -> Any:
+        """Return underlying (not-necessarily-Standard-compliant) scalar object."""
+        ...
+
     def __lt__(self, other: AnyScalar) -> Scalar:
         ...