[3.14] gh-132642: document how to render human-readable `timedelta` objects (GH-133825) (#133837)

gh-132642: document how to render human-readable `timedelta` objects (GH-133825)
(cherry picked from commit efcc42ba70fb09333a2be16401da731662e2984b)

Co-authored-by: Kentaro Jay Takahashi <64148935+KentaroJay@users.noreply.github.com>