DOC: Mention black and PEP8 in pandas style guide (#32043)

Author: raisadz

Diff for: doc/source/development/code_style.rst

@@ -9,6 +9,12 @@ pandas code style guide
 .. contents:: Table of contents:
    :local:
 
+*pandas* follows the `PEP8 <https://www.python.org/dev/peps/pep-0008/>`_
+standard and uses `Black <https://black.readthedocs.io/en/stable/>`_
+and `Flake8 <https://flake8.pycqa.org/en/latest/>`_ to ensure a
+consistent code format throughout the project. For details see the
+:ref:`contributing guide to pandas<contributing.code-formatting>`.
+
 Patterns
 ========