update whatsnew

Author: jreback

doc/source/whatsnew/v0.24.0.rst

@@ -432,7 +432,7 @@ Backwards incompatible API changes
 - The column order of the resultant :class:`DataFrame` from :meth:`MultiIndex.to_frame` is now guaranteed to match the :attr:`MultiIndex.names` order. (:issue:`22420`)
 - Incorrectly passing a :class:`DatetimeIndex` to :meth:`MultiIndex.from_tuples`, rather than a sequence of tuples, now raises a ``TypeError`` rather than a ``ValueError`` (:issue:`24024`)
 - :func:`pd.offsets.generate_range` argument ``time_rule`` has been removed; use ``offset`` instead (:issue:`24157`)
-- In 0.23.x, pandas would raise a ``ValueError`` on a merge of a numeric column (e.g. ``int`` dtyped column) and an ``object`` dtyped column (:issue:`9780`). We have re-enabled the ability to merge ``object`` and other dtypes (:issue:`21681`)
+- In 0.23.x, pandas would raise a ``ValueError`` on a merge of a numeric column (e.g. ``int`` dtyped column) and an ``object`` dtyped column, though only if it is a numeric column (:issue:`9780`). We have re-enabled the ability to merge ``object`` and other dtypes; pandas will sill raise on a merge between a numeric and an ``object`` dtyped coumn that is composed only of strings (:issue:`21681`)
 
 Percentage change on groupby
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