added what's new entry.

Author: Alex Volkov

doc/source/whatsnew/v0.24.0.txt

@@ -19,6 +19,7 @@ New features
   the user to override the engine's default behavior to include or omit the
   dataframe's indexes from the resulting Parquet file. (:issue:`20768`)
 - :meth:`DataFrame.corr` and :meth:`Series.corr` now accept a callable for generic calculation methods of correlation, e.g. histogram intersection (:issue:`22684`)
+- Script ``validate_docstrings.py`` now displays 'No docstring found' error for the methods where docstrings are missing
 
 
 .. _whatsnew_0240.enhancements.extension_array_operators: