Remove `std` feature; leverage `core::error::Error` #1800

Job	Run time
minimal-versions	22s
test (i686-unknown-linux-gnu, 1.81.0, sudo apt update && sudo apt install gcc-multilib)	53s
test (i686-unknown-linux-gnu, stable, sudo apt update && sudo apt install gcc-multilib)	51s
test (x86_64-unknown-linux-gnu, 1.81.0)	41s
build (1.81.0, thumbv7em-none-eabi)	14s
build-benchmarks	45s
test (x86_64-unknown-linux-gnu, stable)	35s
careful	1m 17s
build (1.81.0, wasm32-unknown-unknown)	16s
build (stable, thumbv7em-none-eabi)	10s
clippy	20s
cross (aarch64-unknown-linux-gnu, stable)	1m 41s
build (stable, wasm32-unknown-unknown)	14s
doc	24s
cross (powerpc-unknown-linux-gnu, stable)	1m 43s
miri (x86_64-unknown-linux-gnu)	45s
rustfmt	6s
miri (s390x-unknown-linux-gnu)	55s
	12m 12s

Provide feedback