Add note that some multiprocessing examples don't work in the repl

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2021-11-28.04:37:54.305>
labels = ['3.11', 'type-bug', 'OS-windows', 'docs']
title = 'Very first multiprocessing example not working on Windows 11'
updated_at = <Date 2021-12-04.07:37:31.190>
user = 'https://github.com/quattrozhou'

bugs.python.org fields:

activity = <Date 2021-12-04.07:37:31.190>
actor = 'eryksun'
assignee = 'docs@python'
closed = False
closed_date = None
closer = None
components = ['Documentation', 'Windows']
creation = <Date 2021-11-28.04:37:54.305>
creator = 'quattrozhou'
dependencies = []
files = []
hgrepos = []
issue_num = 45914
keywords = []
message_count = 4.0
messages = ['407186', '407189', '407638', '407646']
nosy_count = 9.0
nosy_names = ['rhettinger', 'terry.reedy', 'paul.moore', 'tim.golden', 'docs@python', 'zach.ware', 'eryksun', 'steve.dower', 'quattrozhou']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue45914'
versions = ['Python 3.11']