Fix PEP urls.

pep-0006.txt

@@ -203,10 +203,10 @@ References
     [1] http://www.tcl.tk/cgi-bin/tct/tip/28.html
 
     [2] PEP 3, Guidelines for Handling Bug Reports, Hylton
-        http://www.python.org/dev/peps/pep-0003.html
+        http://www.python.org/dev/peps/pep-0003/
 
     [3] PEP 235, Import on Case-Insensitive Platforms, Peters
-        http://www.python.org/dev/peps/pep-0235.html
+        http://www.python.org/dev/peps/pep-0235/
 
 
 Copyright

pep-0007.txt

@@ -201,7 +201,7 @@ Documentation Strings
 References
 
     [1] PEP 8, Style Guide for Python Code, van Rossum, Warsaw
-        http://www.python.org/dev/peps/pep-0008.html
+        http://www.python.org/dev/peps/pep-0008/
 
 
 Copyright

pep-0009.txt

@@ -188,12 +188,12 @@ Plaintext PEP Formatting Requirements
         References
 
             [7] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton
-                http://www.python.org/dev/peps/pep-0001.html
+                http://www.python.org/dev/peps/pep-0001/
 
     If you decide to provide an explicit URL for a PEP, please use
     this as the URL template:
 
-        http://www.python.org/dev/peps/pep-xxxx
+        http://www.python.org/dev/peps/pep-xxxx/
 
     PEP numbers in URLs must be padded with zeros from the left, so as
     to be exactly 4 characters wide, however PEP numbers in the text
@@ -203,10 +203,10 @@ Plaintext PEP Formatting Requirements
 References
 
     [1] PEP 1, PEP Purpose and Guidelines, Warsaw, Hylton
-        http://www.python.org/dev/peps/pep-0001
+        http://www.python.org/dev/peps/pep-0001/
 
     [2] PEP 12, Sample reStructuredText PEP Template, Goodger, Warsaw
-        http://www.python.org/dev/peps/pep-0012
+        http://www.python.org/dev/peps/pep-0012/
 
     [3] http://www.opencontent.org/openpub/