add os.syncfs()

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2016-08-27.18:17:12.953>
labels = ['type-feature', 'library', '3.11']
title = 'add os.syncfs()'
updated_at = <Date 2021-10-10.13:06:05.689>
user = 'https://github.com/socketpair'

bugs.python.org fields:

activity = <Date 2021-10-10.13:06:05.689>
actor = 'nirs'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2016-08-27.18:17:12.953>
creator = 'socketpair'
dependencies = []
files = []
hgrepos = []
issue_num = 27879
keywords = []
message_count = 4.0
messages = ['273790', '273888', '273900', '403584']
nosy_count = 4.0
nosy_names = ['fdrake', 'nirs', 'socketpair', 'josh.r']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue27879'
versions = ['Python 3.11']