Start the deprecation cycle for subprocess preexec_fn

GitHub fields:

assignee = 'https://github.com/gpshead'
closed_at = None
created_at = <Date 2019-10-10.18:18:17.382>
labels = ['type-feature', 'library', '3.11']
title = 'Start the deprecation cycle for subprocess preexec_fn'
updated_at = <Date 2022-03-16.16:54:37.730>
user = 'https://github.com/gpshead'

bugs.python.org fields:

activity = <Date 2022-03-16.16:54:37.730>
actor = 'markmentovai'
assignee = 'gregory.p.smith'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2019-10-10.18:18:17.382>
creator = 'gregory.p.smith'
dependencies = []
files = []
hgrepos = []
issue_num = 38435
keywords = ['patch']
message_count = 18.0
messages = ['354397', '354404', '354407', '354439', '383708', '383720', '383724', '383725', '383726', '383727', '383728', '383736', '383740', '383863', '383988', '400498', '403026', '415352']
nosy_count = 6.0
nosy_names = ['gregory.p.smith', 'vstinner', 'diekhans', 'markmentovai', 'serhiy.storchaka', 'izbyshev']
pr_nums = ['23930', '23936']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue38435'
versions = ['Python 3.11']