help() of bitwise operators should mention sets as well

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2017-12-23.04:35:29.731>
labels = ['type-feature', '3.7', 'docs']
title = 'help() of bitwise operators should mention sets as well'
updated_at = <Date 2017-12-23.16:24:04.746>
user = 'https://github.com/stevendaprano'

bugs.python.org fields:

activity = <Date 2017-12-23.16:24:04.746>
actor = 'r.david.murray'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2017-12-23.04:35:29.731>
creator = 'steven.daprano'
dependencies = []
files = []
hgrepos = []
issue_num = 32412
keywords = []
message_count = 2.0
messages = ['308946', '308956']
nosy_count = 3.0
nosy_names = ['steven.daprano', 'r.david.murray', 'docs@python']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue32412'
versions = ['Python 3.7']