Makes the reference types sound via a DST (#1532) #528

Job	Run time
nostd/thumbv6m-none-eabi/stable	18s
clippy/stable	25s
Pass MSRV values to other jobs	4s
format/nightly	15s
docs/nightly	21s
miri	10m 57s
cross_test/i686-unknown-linux-gnu/stable	2m 37s
cross_test/s390x-unknown-linux-gnu/stable	8m 41s
cargo-careful	2m 16s
blas-msrv	1m 15s
tests/beta	2m 57s
tests/stable	2m 46s
tests/1.64.0	9m 4s
tests/nightly	3m 12s
conclusion	3s
	45m 11s

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