Elaborate the format of the Change History section

* Specify MMM-DD-YYYY bullets
* Specify reverse chronological order
* Fix a typo and standardize capitalization

Author: warsaw

peps/pep-0001.rst

@@ -583,9 +583,11 @@ Each PEP should have the following parts/sections:
 
 14. Change History -- A summary of major changes the PEP has undergone, based on discussions and feedback.
     Think of this as a "changelog" or "release notes" for the PEP.  In general, whenever you update the
-    ``Post-History`` header for major changes, consider adding a dated entry in this section.  This isn't
-    mandatory, so it's left to the  PEP author's discretion, but such a section can be helpful for those
-    following along to understand the evolution of your PEP.  Here is :pep:`an example <694#change-history>`.
+    ``Post-History`` header for major changes, add a new bullet item in newest-first (i.e. reverse
+    chronological) order, using the same ``MMM-DD-YYYY`` format, with sub-bullets summarizing the changes.
+    This isn't mandatory, so it's left to the PEP author's discretion, but such a section can be helpful for
+    those following along to understand the evolution of your PEP.  Here is :pep:`an example
+    <694#change-history>`.
 
 15. Copyright/license -- Each new PEP must be placed under a dual license of
     public domain and CC0-1.0-Universal_ (see this PEP for an example).

peps/pep-0012.rst

@@ -100,8 +100,8 @@ directions below.
   feature is described in a Final PEP.
 
 - Change the Created header to today's date.  Be sure to follow the
-  format carefully: it must be in ``dd-mmm-yyyy`` format, where the
-  ``mmm`` is the 3 English letter month abbreviation, i.e. one of Jan,
+  format carefully: it must be in ``DD-MMM-YYYY`` format, where the
+  ``MMM`` is the 3 English letter month abbreviation, i.e. one of Jan,
   Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec.
 
 - For Standards Track PEPs, after the Created header, add a
@@ -122,7 +122,7 @@ directions below.
 - Post-History can be 'Pending' for now; you'll add dates and corresponding links
   to this header each time you post your PEP to the designated discussion forum
   (and update the Discussions-To header with said link, as above).
-  For each thread, use the date (in the ``dd-mmm-yyy`` format) as the
+  For each thread, use the date (in the ``DD-MMM-YYYY`` format) as the
   linked text, and insert the URLs inline as anonymous reST `hyperlinks`_,
   with commas in between each posting.
 

peps/pep-0012/pep-NNNN.rst

@@ -91,8 +91,9 @@ Footnotes
 Change History
 ==============
 
-[A summary of major changes the PEP has undergone.  Add a dated entry here whenever you update the
-``Post-History`` header.]
+[A summary of major changes the PEP has undergone.  Whenever you update the ``Post-History``, add a new bullet
+item in newest-first (i.e. reverse chronological) order, using the same ``MMM-DD-YYYY`` format, with
+sub-bullets summarizing the changes.]
 
 
 Copyright