Changed the "write your own settings" recommendation to mention that Django

uses tuples, but not making it a recommendation. That might head off the endless
tuples vs. lists debates.

Fixed #8846.


git-svn-id: http://code.djangoproject.com/svn/django/trunk@9146 bcc190cf-cafb-0310-a4f2-bffc1f526a37

docs/topics/settings.txt

@@ -160,10 +160,11 @@ There's nothing stopping you from creating your own settings, for your own
 Django apps. Just follow these conventions:
 
     * Setting names are in all uppercase.
-    * For settings that are sequences, use tuples instead of lists. This is
-      purely for performance.
     * Don't reinvent an already-existing setting.
 
+For settings that are sequences, Django itself uses tuples, rather than lists,
+but this is only a convention.
+
 .. _settings-without-django-settings-module:
 
 Using settings without setting DJANGO_SETTINGS_MODULE