implement dot for higher-dimensional arrays with Ix2 #683

Job	Run time
clippy/stable	21s
format/nightly	13s
miri	10m 45s
cross_test/s390x-unknown-linux-gnu/stable	8m 0s
cargo-careful	2m 15s
docs/nightly	23s
Pass MSRV values to other jobs	2s
nostd/thumbv6m-none-eabi/stable	18s
cross_test/i686-unknown-linux-gnu/stable	2m 5s
blas-msrv	49s
tests/beta	3m 3s
tests/stable	2m 35s
tests/1.87.0	2m 32s
tests/nightly	3m 56s
conclusion	0s
	37m 17s

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