Documenting dataclass and namedtuple changes for structural pattern matching

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-04-07.10:40:27.457>
labels = ['3.10', 'docs']
title = 'Documenting dataclass and namedtuple changes for structural pattern matching'
updated_at = <Date 2021-04-12.16:35:21.092>
user = 'https://github.com/freundTech'

bugs.python.org fields:

activity = <Date 2021-04-12.16:35:21.092>
actor = 'brandtbucher'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2021-04-07.10:40:27.457>
creator = 'freundTech'
dependencies = []
files = []
hgrepos = []
issue_num = 43761
keywords = []
message_count = 12.0
messages = ['390413', '390426', '390430', '390457', '390676', '390679', '390685', '390692', '390707', '390725', '390733', '390865']
nosy_count = 6.0
nosy_names = ['gvanrossum', 'rhettinger', 'eric.smith', 'docs@python', 'brandtbucher', 'freundTech']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue43761'
versions = ['Python 3.10']