Remove last mention of `stdsimd` #1925

Job	Run time
Check Style	13s
Automatic intrinsic verification	26s
Build Documentation	1m 4s
Env Override	13s
Build std_detect	59s
Test (i686-unknown-linux-gnu)	1m 52s
Test (x86_64-unknown-linux-gnu)	3m 40s
Test (x86_64-unknown-linux-gnu-emulated)	9m 18s
Test (arm-unknown-linux-gnueabihf)	1m 24s
Test (armv7-unknown-linux-gnueabihf)	10m 53s
Test (aarch64-unknown-linux-gnu)	21m 53s
Test (riscv64gc-unknown-linux-gnu)	1m 23s
Test (powerpc64le-unknown-linux-gnu)	3m 43s
Test (s390x-unknown-linux-gnu)	1m 25s
Test (wasm32-wasi)	1m 40s
Test (i586-unknown-linux-gnu)	1m 52s
Test (nvptx64-nvidia-cuda)	33s
Test (thumbv6m-none-eabi)	12s
Test (thumbv7m-none-eabi)	12s
Test (thumbv7em-none-eabi)	12s
Test (thumbv7em-none-eabihf)	12s
Test (aarch64-apple-darwin)	2m 0s
Test (x86_64-pc-windows-msvc)	6m 13s
Test (i686-pc-windows-msvc)	2m 48s
Test (x86_64-apple-darwin, macos-11)	7m 18s
success	1s
	1h 21m 39s

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