[3.7] bpo-31201: Clarify command to re-run failing test(s) with example (GH-6417) (GH-6437)

(cherry picked from commit 0f914b5b5f6ba186afd7112fc851c97247076f70)

Co-authored-by: Aaron Ang <aaronang@users.noreply.github.com>
1 file changed