[3.13] Delete stale note about mp.Lock.acquire/SIGINT (GH-120929) (GH-122078)

Delete stale note about mp.Lock.acquire/SIGINT (GH-120929)
(cherry picked from commit 0dcbc8385322ff51f7fc3e586027d880275df4fa)

Co-authored-by: Andrey Mishchenko <mishchea@gmail.com>
1 file changed