Linkify PEP 8 in unix.rst (GH-10482)

(cherry picked from commit 9404e773)
Co-authored-by: Andrés Delfino <adelfino@gmail.com>

Doc/using/unix.rst

@@ -142,7 +142,7 @@ Editors and IDEs
 ================
 
 There are a number of IDEs that support Python programming language.
-Many editors and IDEs provide syntax highlighting, debugging tools, and PEP-8 checks.
+Many editors and IDEs provide syntax highlighting, debugging tools, and :pep:`8` checks.
 
 Please go to `Python Editors <https://wiki.python.org/moin/PythonEditors>`_ and
 `Integrated Development Environments <https://wiki.python.org/moin/IntegratedDevelopmentEnvironments>`_