Docs: Clarify the before_and_after() example (GH-28458) (#28464)

(cherry picked from commit fcbf9b176b1190301c760a921601c6488ef8b070)

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>

Co-authored-by: Raymond Hettinger <rhettinger@users.noreply.github.com>
2 files changed