difflib.get_close_matches: Add `key` argument

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-05-16.16:14:00.944>
labels = ['type-feature', 'library', '3.11']
title = 'difflib.get_close_matches: Add `key` argument'
updated_at = <Date 2021-05-16.17:25:58.375>
user = 'https://github.com/mustafaquraish'

bugs.python.org fields:

activity = <Date 2021-05-16.17:25:58.375>
actor = 'rhettinger'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2021-05-16.16:14:00.944>
creator = 'mustafaquraish'
dependencies = []
files = []
hgrepos = []
issue_num = 44149
keywords = ['patch']
message_count = 1.0
messages = ['393747']
nosy_count = 3.0
nosy_names = ['tim.peters', 'python-dev', 'mustafaquraish']
pr_nums = ['26170']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue44149'
versions = ['Python 3.11']