string.Formatter.parse does not handle auto-numbered positional fields

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-11-03.11:55:47.784>
labels = ['type-bug', '3.8', '3.9', '3.10', '3.11', '3.7']
title = 'string.Formatter.parse does not handle auto-numbered positional fields'
updated_at = <Date 2021-11-05.18:06:11.745>
user = 'https://bugs.python.org/SDesch'

bugs.python.org fields:

activity = <Date 2021-11-05.18:06:11.745>
actor = 'eric.smith'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2021-11-03.11:55:47.784>
creator = 'SDesch'
dependencies = []
files = []
hgrepos = []
issue_num = 45704
keywords = []
message_count = 9.0
messages = ['405610', '405619', '405624', '405627', '405636', '405757', '405796', '405802', '405814']
nosy_count = 2.0
nosy_names = ['eric.smith', 'SDesch']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45704'
versions = ['Python 3.6', 'Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10', 'Python 3.11']