chore: add a witness for `enum_variant_missing` #2934

Job	Run time
Build binary	46s
Build binary (Windows)	2m 56s
Check lint and rustfmt	29s
Semver: core-graphics	46s
Run tests (1.77, false)	2m 40s
Check if version changed	18s
Run tests (1.78, false)	3m 0s
Run tests (1.79, false)	2m 46s
Run tests (1.80, false)	2m 47s
Run tests (1.81, false)	2m 50s
Run tests (stable, false)	2m 43s
Run tests (beta, false)	2m 41s
Run tests (nightly, true)	2m 33s
Semver: libp2p-core 0.37.0	53s
Caching with feature config changed	27s
Semver: bevy_core v0.9.0	37s
Caching across rustdoc versions	1m 34s
Semver: bevy_gltf v0.9.1	58s
Semver: libp2p-dcutr 1.62.0 and libp2p-relay 0.14.0	1m 10s
Semver: libp2p-gossipsub ~0.44.0 + libp2p-request-response ~0.24.0	1m 12s
Semver: libp2p-uds 0.37.0	1m 0s
Semver: sqllogictest v0.13.0	36s
Check failure when installed rustc is too old	23s
Semver: clap v3.2.0	44s
Semver: dependency has warnings with "-Dwarnings" (libp2p v0.53.1)	1m 8s
Semver: perf-event-open-sys2 v5.0.0	19s
Semver: ref-slice fork (git)	27s
Semver: tokio ~v1.25.0 (explicit)	5s
Semver: tokio ~v1.25.0 (implicit)	4s
Semver: ref-slice fork (sparse)	21s
Semver: ref-slice fork (Windows) (git)	55s
Semver: ref-slice fork (Windows) (sparse)	47s
All CI stages	1s
Check for semver compliance	0s
Run the release workflow	0s
	40m 56s

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