Meta: Document the shortcut links (#3043)

Co-authored-by: C.A.M. Gerlach <[email protected]>

Author: hugovk

README.rst

@@ -10,6 +10,16 @@ about writing one, please start reading at :pep:`1`. Note that the PEP Index
 (:pep:`0`) is automatically generated based on the metadata headers in other PEPs.
 
 
+Canonical links
+===============
+
+The canonical form of PEP links are zero-padded, such as
+``https://peps.python.org/pep-0008/``
+
+Shortcut redirects are also available.
+For example, ``https://peps.python.org/8`` redirects to the canonical link.
+
+
 Contributing to PEPs
 ====================