Guarantee return value of `serve`, Pt. 2 (#3166) #5262

Job	Run time
check-docs	20s
cargo-hack	2m 55s
cargo-public-api-crates (axum)	36s
check	39s
cargo-public-api-crates (axum-core)	20s
cargo-deny check (advisories)	26s
dependencies-are-sorted	18s
cargo-public-api-crates (axum-extra)	30s
cargo-deny check (bans licenses sources)	26s
cargo-public-api-crates (axum-macros)	12s
Spell Check with Typos	6s
test-msrv	2m 11s
test-docs	1m 27s
test-nightly	1m 3s
armv5te-unknown-linux-musleabi	32s
test-versions (stable)	1m 17s
test-versions (beta)	1m 10s
wasm32-unknown-unknown	17s
	14m 45s

Provide feedback