feat: add `AsRef` impl and `hash` method to `Sealed` #2157

Job	Run time
docs	57s
check no_std	46s
features stable	2m 16s
clippy	1m 12s
features stable --all-targets	3m 21s
fmt	14s
features nightly	2m 40s
miri --no-default-features	5m 4s
miri	5m 13s
features nightly --all-targets	3m 30s
miri --all-features	7m 46s
wasm	32s
test ubuntu-latest stable --no-default-features	1m 9s
test ubuntu-latest stable	1m 10s
test ubuntu-latest nightly --no-default-features	1m 15s
test ubuntu-latest nightly	1m 22s
test ubuntu-latest 1.79 --no-default-features	38s
test ubuntu-latest 1.79	35s
test windows-latest stable --no-default-features	4m 11s
test windows-latest stable	3m 37s
test windows-latest nightly --no-default-features	3m 1s
test windows-latest nightly	2m 56s
test windows-latest 1.79 --no-default-features	1m 26s
test windows-latest 1.79	1m 30s
test ubuntu-latest 1.79 --features json	38s
test windows-latest 1.79 --features json	1m 28s
test ubuntu-latest nightly --all-features	1m 25s
test windows-latest nightly --all-features	3m 16s
ci success	2s
	1h 3m 10s

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