Abstract property setter/deleter implementation not enforced, but documented as such

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-02-21.10:59:10.737>
labels = ['type-bug', '3.8', '3.9', '3.10', '3.7', 'docs']
title = 'Abstract property setter/deleter implementation not enforced, but documented as such'
updated_at = <Date 2020-12-09.22:45:34.731>
user = 'https://bugs.python.org/arnvollebregtkpn'

bugs.python.org fields:

activity = <Date 2020-12-09.22:45:34.731>
actor = 'gvanrossum'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2020-02-21.10:59:10.737>
creator = 'arn.vollebregt.kpn'
dependencies = []
files = []
hgrepos = []
issue_num = 39707
keywords = []
message_count = 5.0
messages = ['362403', '362413', '362438', '382810', '382811']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'rhettinger', 'docs@python', 'josh.r', 'arn.vollebregt.kpn']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue39707'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10']