DOC: clean-up 0.23.2 whatsnew file (pandas-dev#21750)

Author: jorisvandenbossche

doc/source/whatsnew/v0.23.2.txt

@@ -63,12 +63,6 @@ Fixed Regressions
 - Fixed regression in :func:`to_clipboard` that defaulted to copying dataframes with space delimited instead of tab delimited (:issue:`21104`)
 
 
-Documentation Changes
-~~~~~~~~~~~~~~~~~~~~~
-
--
--
-
 Build Changes
 -------------
 
@@ -79,56 +73,32 @@ Build Changes
 Bug Fixes
 ~~~~~~~~~
 
-**Groupby/Resample/Rolling**
-
--
--
-
-**Timedelta**
-
-- Bug in :class:`Timedelta` where non-zero timedeltas shorter than 1 microsecond were considered False (:issue:`21484`)
-
 **Conversion**
 
 - Bug in constructing :class:`Index` with an iterator or generator (:issue:`21470`)
 - Bug in :meth:`Series.nlargest` for signed and unsigned integer dtypes when the minimum value is present (:issue:`21426`)
 
-
 **Indexing**
 
 - Bug in :meth:`Index.get_indexer_non_unique` with categorical key (:issue:`21448`)
 - Bug in comparison operations for :class:`MultiIndex` where error was raised on equality / inequality comparison involving a MultiIndex with ``nlevels == 1`` (:issue:`21149`)
 - Bug in :meth:`DataFrame.drop` behaviour is not consistent for unique and non-unique indexes (:issue:`21494`)
 - Bug in :func:`DataFrame.duplicated` with a large number of columns causing a 'maximum recursion depth exceeded' (:issue:`21524`).
--
 
 **I/O**
 
 - Bug in :func:`read_csv` that caused it to incorrectly raise an error when ``nrows=0``, ``low_memory=True``, and ``index_col`` was not ``None`` (:issue:`21141`)
 - Bug in :func:`json_normalize` when formatting the ``record_prefix`` with integer columns (:issue:`21536`)
--
-
-**Plotting**
-
--
--
-
-**Reshaping**
-
--
--
 
 **Categorical**
 
 - Bug in rendering :class:`Series` with ``Categorical`` dtype in rare conditions under Python 2.7 (:issue:`21002`)
--
 
 **Timezones**
 
 - Bug in :class:`Timestamp` and :class:`DatetimeIndex` where passing a :class:`Timestamp` localized after a DST transition would return a datetime before the DST transition (:issue:`20854`)
 - Bug in comparing :class:`DataFrame`s with tz-aware :class:`DatetimeIndex` columns with a DST transition that raised a ``KeyError`` (:issue:`19970`)
 
+**Timedelta**
 
-**Other**
-
--
+- Bug in :class:`Timedelta` where non-zero timedeltas shorter than 1 microsecond were considered False (:issue:`21484`)