add links

Author: Raisa Dzhamtyrova

doc/source/development/code_style.rst

@@ -9,6 +9,13 @@ 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
+`contributing guide to pandas
+<https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#python-pep8-black>`_.
+
 Patterns
 ========
 
@@ -128,12 +135,6 @@ For example:
     value = str
     f"Unknown received type, got: '{type(value).__name__}'"
 
-PEP8 / black
-------------
-pandas follows the PEP8 standard and uses Black and Flake8 to ensure a
-consistent code format throughout the project. For details see the
-contributing guide https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#python-pep8-black.
-
 Imports (aim for absolute)
 ==========================