fmt/rfc2822: add routines explicitly for RFC 9110 #557

Job	Run time
win-gnu	2m 16s
test (stable, ubuntu-latest, stable)	5m 58s
test (beta, ubuntu-latest, beta)	6m 6s
msrv	1m 20s
cross (i686-unknown-linux-gnu)	1m 39s
test (nightly, ubuntu-latest, nightly)	4m 24s
rustfmt	13s
cross (aarch64-unknown-linux-gnu)	1m 47s
test (macos, macos-latest, stable)	3m 50s
testbench	58s
test (win-msvc, windows-latest, stable)	5m 23s
wasm32-unknown-emscripten	1m 55s
cross (powerpc-unknown-linux-gnu)	2m 3s
wasm32-unknown-uknown	26s
cross (powerpc64-unknown-linux-gnu)	1m 51s
wasm32-wasip1	1m 2s
cross (s390x-unknown-linux-gnu)	2m 8s
	43m 19s

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