argparse: customizable help formatter

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-01-19.14:27:00.579>
labels = ['type-feature', 'library', '3.10']
title = 'argparse: customizable help formatter'
updated_at = <Date 2021-01-29.21:27:53.846>
user = 'https://github.com/monkeyman79'

bugs.python.org fields:

activity = <Date 2021-01-29.21:27:53.846>
actor = 'monkeyman79'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-01-19.14:27:00.579>
creator = 'monkeyman79'
dependencies = []
files = ['49750']
hgrepos = []
issue_num = 42966
keywords = ['patch']
message_count = 3.0
messages = ['385263', '385509', '385942']
nosy_count = 3.0
nosy_names = ['rhettinger', 'paul.j3', 'monkeyman79']
pr_nums = ['24377']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue42966'
versions = ['Python 3.10']