Use the :pep: tag instead of directly linking PEPs

docs/scenarios/db.rst

@@ -5,7 +5,7 @@ DB-API
 ------
 
 The Python Database API (DB-API) defines a standard interface for Python
-database access modules. It's documented in `PEP 249 <http://www.python.org/dev/peps/pep-0249/>`_.
+database access modules. It's documented in :pep:`249`.
 Nearly all Python database modules such as `sqlite3`, `psycopg` and
 `mysql-python` conform to this interface.
 

docs/scenarios/imaging.rst

@@ -12,7 +12,7 @@ The `Python Imaging Library <http://www.pythonware.com/products/pil/>`_, or PIL
 for short, is *the* library for image manipulation in Python. Unfortunately, its
 development has stagnated, with its last release in 2009.
 
-Lucky for you, there's an actively-developed fork of PIL called `Pillow <http://python-imaging.github.io/>`_ -
+Luckily for you, there's an actively-developed fork of PIL called `Pillow <http://python-imaging.github.io/>`_ -
 it's easier to install, runs on all operating systems, and supports Python 3.
 
 Installation

docs/scenarios/web.rst

@@ -18,7 +18,7 @@ interface between web servers and Python web application frameworks. By
 standardizing behavior and communication between web servers and Python web
 frameworks, WSGI makes it possible to write portable Python web code that
 can be deployed in any :ref:`WSGI-compliant web server <wsgi-servers-ref>`.
-WSGI is documented in `PEP-3333 <http://www.python.org/dev/peps/pep-3333/>`_.
+WSGI is documented in :pep:`3333`.
 
 
 Frameworks