add back one doc okwarning

Author: jorisvandenbossche

doc/source/user_guide/pyarrow.rst

@@ -104,6 +104,7 @@ To convert a :external+pyarrow:py:class:`pyarrow.Table` to a :class:`DataFrame`,
 :external+pyarrow:py:meth:`pyarrow.Table.to_pandas` method with ``types_mapper=pd.ArrowDtype``.
 
 .. ipython:: python
+   :okwarning:
 
    table = pa.table([pa.array([1, 2, 3], type=pa.int64())], names=["a"])