Implement STB 34.101.77-2020 `bash` #241

Job	Run time
miri (x86_64-unknown-linux-gnu)	46s
miri (s390x-unknown-linux-gnu)	1m 6s
test-simd	17s
set-msrv / set-msrv	5s
minimal-versions / minimal-versions	32s
test (stable)	36s
test (1.85.0)	14s
build (1.85.0, wasm32-unknown-unknown)	15s
aarch64-sha3 (1.85.0)	34s
build (stable, wasm32-unknown-unknown)	13s
build (stable, thumbv7em-none-eabi)	24s
build (1.85.0, thumbv7em-none-eabi)	19s
aarch64-sha3 (stable)	39s
	6m 0s

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