Link to class and function source code on GitHub

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-02-12.23:09:53.491>
labels = ['type-feature', '3.10', 'docs']
title = 'Link to class and function source code on GitHub'
updated_at = <Date 2021-02-12.23:09:53.491>
user = 'https://github.com/verhovsky'

bugs.python.org fields:

activity = <Date 2021-02-12.23:09:53.491>
actor = 'boris'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2021-02-12.23:09:53.491>
creator = 'boris'
dependencies = []
files = []
hgrepos = []
issue_num = 43212
keywords = []
message_count = 1.0
messages = ['386889']
nosy_count = 2.0
nosy_names = ['docs@python', 'boris']
pr_nums = ['24521']
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue43212'
versions = ['Python 3.10']