[3.7] bpo-33319: Clarify subprocess call docs. (GH-12508) by miss-islington · Pull Request #12509

[3.7] bpo-33319: Clarify subprocess call docs. (GH-12508) by miss-islington · Pull Request #12509 · python/cpython

Clarify capturing or suppressing stdout and stderr on the old call APIs.

Do not state that they are equivalent to run() calls when they are not implemented using run as that was misleading. Unlike run they cannot handle stdout or stderr being set to PIPE without a risk of deadlock.
(cherry picked from commit 7a2e84c)

Co-authored-by: Gregory P. Smith <greg@krypto.org>