Make multiprocessing.connection.Client support ipv6

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2022-02-20.17:36:46.631>
labels = ['type-bug', '3.9']
title = 'Make multiprocessing.connection.Client support ipv6'
updated_at = <Date 2022-02-25.20:29:58.919>
user = 'https://bugs.python.org/mhupfer'

bugs.python.org fields:

activity = <Date 2022-02-25.20:29:58.919>
actor = 'terry.reedy'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2022-02-20.17:36:46.631>
creator = 'mhupfer'
dependencies = []
files = []
hgrepos = []
issue_num = 46810
keywords = []
message_count = 1.0
messages = ['413599']
nosy_count = 3.0
nosy_names = ['pitrou', 'davin', 'mhupfer']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue46810'
versions = ['Python 3.9']