Improve `debug_handler` on tuple response types #4245

Job	Run time
check	49s
cargo-public-api-crates (axum)	35s
cargo-hack	2m 53s
check-docs	20s
cargo-public-api-crates (axum-core)	19s
cargo-public-api-crates (axum-extra)	32s
cargo-deny check (advisories)	24s
dependencies-are-sorted	14s
cargo-deny check (bans licenses sources)	23s
cargo-public-api-crates (axum-macros)	18s
Spell Check with Typos	4s
test-docs	1m 29s
test-versions (stable)	1m 59s
test-versions (beta)	1m 52s
armv5te-unknown-linux-musleabi	34s
test-msrv	2m 18s
test-nightly	1m 32s
wasm32-unknown-unknown	24s
	16m 59s

Provide feedback