Remove redundant leading zeroes in PEP references.
diff --git a/Doc/library/weakref.rst b/Doc/library/weakref.rst
index 1c3cdbb..e5a99ea 100644
--- a/Doc/library/weakref.rst
+++ b/Doc/library/weakref.rst
@@ -245,7 +245,7 @@
 
 .. seealso::
 
-   :pep:`0205` - Weak References
+   :pep:`205` - Weak References
       The proposal and rationale for this feature, including links to earlier
       implementations and information about similar features in other languages.