Fixed #26580 -- Updated references to obsolete RFC 2822.

Didn't rename django.utils.feedgenerator.rfc2822_date()
as some external code may rely on it.

django/core/mail/message.py

@@ -44,7 +44,7 @@ class BadHeaderError(ValueError):
 # TODO: replace with email.utils.make_msgid(.., domain=DNS_NAME) when dropping
 # Python 2 (Python 2's version doesn't have domain parameter) (#23905).
 def make_msgid(idstring=None, domain=None):
-    """Returns a string suitable for RFC 2822 compliant Message-ID, e.g:
+    """Returns a string suitable for RFC 5322 compliant Message-ID, e.g:
 
     <20020201195627.33539.96671@nightshade.la.mastaler.com>
 

django/utils/dateformat.py

@@ -293,7 +293,7 @@ class DateFormat(TimeFormat):
         return self.data.isocalendar()[0]
 
     def r(self):
-        "RFC 2822 formatted date; e.g. 'Thu, 21 Dec 2000 16:01:07 +0200'"
+        "RFC 5322 formatted date; e.g. 'Thu, 21 Dec 2000 16:01:07 +0200'"
         return self.format('D, j M Y H:i:s O')
 
     def S(self):

docs/ref/templates/builtins.txt

@@ -1352,7 +1352,7 @@ P                 Time, in 12-hour hours, minutes and       ``'1 a.m.'``, ``'1:3
                   if they're zero and the special-case
                   strings 'midnight' and 'noon' if
                   appropriate. Proprietary extension.
-r                 :rfc:`2822` formatted date.               ``'Thu, 21 Dec 2000 16:01:07 +0200'``
+r                 :rfc:`5322` formatted date.               ``'Thu, 21 Dec 2000 16:01:07 +0200'``
 s                 Seconds, 2 digits with leading zeros.     ``'00'`` to ``'59'``
 S                 English ordinal suffix for day of the     ``'st'``, ``'nd'``, ``'rd'`` or ``'th'``
                   month, 2 characters.