Adds an array reference type #409

Job	Run time
Pass MSRV values to other jobs	2s
nostd/thumbv6m-none-eabi/stable	10s
miri	8m 13s
clippy/stable	10s
cross_test/s390x-unknown-linux-gnu/stable	7m 42s
cross_test/i686-unknown-linux-gnu/stable	1m 17s
cargo-careful	1m 53s
format/nightly	12s
docs/nightly	18s
tests/beta	2m 34s
tests/nightly	2m 42s
blas-msrv	51s
tests/1.64.0	3m 47s
tests/stable	2m 28s
conclusion	4s
	32m 23s

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