add whatsnew

Author: minggli

doc/source/whatsnew/v0.24.0.txt

@@ -416,15 +416,15 @@ In addition to these API breaking changes, many :ref:`performance improvements a
 Raise ValueError in ``DataFrame.to_dict(orient='index')``
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Bug in :func:`DataFrame.to_dict` raises ``ValueError`` when used with 
+Bug in :func:`DataFrame.to_dict` raises ``ValueError`` when used with
 ``orient='index'`` and a non-unique index instead of losing data (:issue:`22801`)
 
 .. ipython:: python
     :okexcept:
 
     df = pd.DataFrame({'a': [1, 2], 'b': [0.5, 0.75]}, index=['A', 'A'])
     df
-    
+
     df.to_dict(orient='index')
 
 .. _whatsnew_0240.api.datetimelike.normalize:
@@ -706,6 +706,8 @@ Deprecations
   many ``Series``, ``Index`` or 1-dimensional ``np.ndarray``, or alternatively, only scalar values. (:issue:`21950`)
 - :meth:`FrozenNDArray.searchsorted` has deprecated the ``v`` parameter in favor of ``value`` (:issue:`14645`)
 - :func:`DatetimeIndex.shift` and :func:`PeriodIndex.shift` now accept ``periods`` argument instead of ``n`` for consistency with :func:`Index.shift` and :func:`Series.shift`. Using ``n`` throws a deprecation warning (:issue:`22458`, :issue:`22912`)
+- :meth:`pandas.read_csv` has deprecated the redundant ``delimiter`` argument, please use ``sep`` (:issue:`21996`)
+
 
 .. _whatsnew_0240.prior_deprecations: