[3.13] gh-148763: Fix paramter name in `multiprocessing.connection.send_bytes/recv_bytes_into` docs (GH-126603) (#148787)

gh-148763: Fix paramter name in `multiprocessing.connection.send_bytes/recv_bytes_into` docs (GH-126603)
(cherry picked from commit e50acef0b2c2057874a9eec98c37ca6cf8ee98e1)


Doc: Fix buf argument name in multiprocessing connection send_bytes

Co-authored-by: Matthew Davis <7035647+mdavis-xyz@users.noreply.github.com>