chore: shift std::error impls to core #5685

Job	Run time
wasm-unknown	2m 38s
wasm-wasi	3m 37s
check no_std	59s
clippy	1m 28s
docs	58s
doctest	2m 42s
feature-checks	8m 28s
fmt	10s
test ubuntu-latest stable --no-default-features	2m 36s
test ubuntu-latest stable	2m 32s
test ubuntu-latest stable --all-features	3m 1s
test ubuntu-latest nightly --no-default-features	1m 21s
test ubuntu-latest nightly	1m 39s
test ubuntu-latest nightly --all-features	2m 16s
test ubuntu-latest 1.81 --no-default-features	1m 39s
test ubuntu-latest 1.81	1m 44s
test windows-latest stable --no-default-features	7m 28s
test windows-latest stable	5m 21s
test windows-latest stable --all-features	6m 45s
test windows-latest nightly --no-default-features	4m 6s
test windows-latest nightly	3m 47s
test windows-latest nightly --all-features	5m 19s
test windows-latest 1.81 --no-default-features	4m 8s
test windows-latest 1.81	5m 13s
deny / cargo deny check	20s
ci success	2s
	1h 20m 17s

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