update whatsnew files

Author: jorisvandenbossche

doc/source/whatsnew/v2.2.0.rst

@@ -664,6 +664,7 @@ Other Deprecations
 - Deprecated :meth:`DatetimeArray.__init__` and :meth:`TimedeltaArray.__init__`, use :func:`array` instead (:issue:`55623`)
 - Deprecated :meth:`Index.format`, use ``index.astype(str)`` or ``index.map(formatter)`` instead (:issue:`55413`)
 - Deprecated :meth:`Series.ravel`, the underlying array is already 1D, so ravel is not necessary (:issue:`52511`)
+- Deprecated :meth:`Series.resample` and :meth:`DataFrame.resample` with a :class:`PeriodIndex` (and the 'convention' keyword), convert to :class:`DatetimeIndex` (with ``.to_timestamp()``) before resampling instead (:issue:`53481`). Note: this deprecation was later undone in pandas 2.3.3 (:issue:`57033`)
 - Deprecated :meth:`Series.view`, use :meth:`Series.astype` instead to change the dtype (:issue:`20251`)
 - Deprecated :meth:`offsets.Tick.is_anchored`, use ``False`` instead (:issue:`55388`)
 - Deprecated ``core.internals`` members ``Block``, ``ExtensionBlock``, and ``DatetimeTZBlock``, use public APIs instead (:issue:`55139`)

doc/source/whatsnew/v2.3.3.rst

@@ -57,6 +57,14 @@ Bug fixes
 
 - The :meth:`DataFrame.iloc` now works correctly with ``copy_on_write`` option when assigning values after subsetting the columns of a homogeneous DataFrame (:issue:`60309`)
 
+Other changes
+~~~~~~~~~~~~~
+
+- The deprecation of using :meth:`Series.resample` and :meth:`DataFrame.resample`
+  with a :class:`PeriodIndex` (and the 'convention' keyword) has been undone.
+  Resampling with a :class:`PeriodIndex` is supported again, but a subset of
+  methods that return incorrect results will raise an error in pandas 3.0 (:issue:`57033`)
+
 
 .. ---------------------------------------------------------------------------
 .. _whatsnew_233.contributors: