bpo-34804: [doc] Rephrase section on side effects in functional.rst for clarity (GH-27989) (GH-28762)

Co-authored-by: Ɓukasz Langa <lukasz@langa.pl>
(cherry picked from commit 7af95a1e8097b2aab2cbe8de88727809e745b658)

Co-authored-by: DonnaDia <37962843+DonnaDia@users.noreply.github.com>
1 file changed