[3.13] gh-130160: use `.. program::` directive for documenting `http.server` CLI (GH-131010) (#131293)

gh-130160: use `.. program::` directive for documenting `http.server` CLI (GH-131010)
(cherry picked from commit 7ae9c5dd25cccfc4e44fae6c6974ab9f32c5e985)

Co-authored-by: donBarbos <donbarbos@proton.me>