Mark `GroupMetadataV3` and `ArrayMetadataV3` as non-exhaustive #672

Job	Run time
fmt	37s
build_and_test_macos (macos-13)	2m 51s
build_and_test_windows	2m 32s
build_and_test_macos (macos-latest)	1m 7s
build_and_test (stable, --features "")	1m 47s
clippy	49s
build_and_test (stable, --all-features)	2m 12s
build_and_test (stable, --no-default-features)	1m 14s
minimal-versions	36s
build_and_test (1.76, --features "")	1m 51s
codecov	1m 26s
semver	1m 39s
build_and_test (1.76, --all-features)	2m 34s
build_and_test (1.76, --no-default-features)	1m 9s
build_and_test (beta, --features "")	1m 40s
build_and_test (beta, --all-features)	2m 22s
build_and_test (beta, --no-default-features)	1m 13s
build_and_test (nightly, --features "")	1m 26s
build_and_test (nightly, --all-features)	1m 47s
build_and_test (nightly, --no-default-features)	1m 4s
	31m 56s

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