singledispatch does not work with positional arguments with default values.

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2022-03-15.18:46:49.092>
labels = ['type-feature', '3.9', '3.10']
title = 'singledispatch does not work with positional arguments with default values.'
updated_at = <Date 2022-03-22.03:50:00.049>
user = 'https://github.com/randolf-scholz'

bugs.python.org fields:

activity = <Date 2022-03-22.03:50:00.049>
actor = 'andrei.avk'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2022-03-15.18:46:49.092>
creator = 'randolf.scholz'
dependencies = []
files = []
hgrepos = []
issue_num = 47030
keywords = []
message_count = 2.0
messages = ['415274', '415740']
nosy_count = 2.0
nosy_names = ['andrei.avk', 'randolf.scholz']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue47030'
versions = ['Python 3.9', 'Python 3.10']