[doc] Clarify copyreg.pickle() documentation #65022

assignee = None
closed_at = None
created_at = <Date 2014-03-02.08:46:06.048>
labels = ['easy', 'type-bug', '3.9', '3.10', '3.11', 'docs']
title = '[doc] Clarify copyreg.pickle() documentation'
updated_at = <Date 2022-01-18.20:17:10.000>
user = 'https://bugs.python.org/peterotten'

activity = <Date 2022-01-18.20:17:10.000>
actor = 'miss-islington'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2014-03-02.08:46:06.048>
creator = 'peter.otten'
dependencies = []
files = ['34263']
hgrepos = []
issue_num = 20823
keywords = ['patch', 'easy']
message_count = 6.0
messages = ['212541', '288092', '296271', '410883', '410884', '410885']
nosy_count = 5.0
nosy_names = ['peter.otten', 'docs@python', 'serhiy.storchaka', 'miss-islington', 'kumaraditya']
pr_nums = ['30230', '30669', '30670']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue20823'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']