Document that naïve datetime objects represent local time

GitHub fields:

assignee = 'https://github.com/pganssle'
closed_at = None
created_at = <Date 2022-04-05.14:04:48.970>
labels = ['3.11', 'type-feature', '3.9', '3.10', 'docs']
title = 'Document that na\xc3\xafve datetime objects represent local time'
updated_at = <Date 2022-04-05.14:04:48.970>
user = 'https://github.com/pganssle'

bugs.python.org fields:

activity = <Date 2022-04-05.14:04:48.970>
actor = 'p-ganssle'
assignee = 'p-ganssle'
closed = False
closed_date = None
closer = None
components = ['Documentation']
creation = <Date 2022-04-05.14:04:48.970>
creator = 'p-ganssle'
dependencies = []
files = []
hgrepos = []
issue_num = 47228
keywords = []
message_count = 1.0
messages = ['416778']
nosy_count = 2.0
nosy_names = ['belopolsky', 'p-ganssle']
pr_nums = []
priority = 'normal'
resolution = None
stage = 'needs patch'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue47228'
versions = ['Python 3.9', 'Python 3.10', 'Python 3.11']