Simplify how variants are handled #1824

Job	Run time
msrv	1m 29s
docs	2m 59s
clippy	2m 6s
nightly	3m 29s
rustfmt	12s
basics	1s
no_std (ubuntu-latest, minimal)	1m 5s
wasm	1m 10s
no_std (macos-latest, minimal)	1m 8s
test_doc	6m 4s
build_feature (alloc)	3m 39s
build_feature (cli)	3m 51s
test_lib	3m 7s
build_feature (cli,doc)	4m 0s
test_rune	2m 47s
test_miri (rune)	3m 21s
build_feature (cli,fmt)	4m 0s
test_miri (rune-core)	42s
build_feature (doc)	3m 35s
test_miri (rune-alloc)	6m 2s
build_feature (workspace)	3m 23s
build_feature (languageserver)	3m 41s
build_feature (byte-code)	3m 23s
build_feature (capture-io)	3m 23s
build_feature (emit)	3m 22s
	1h 11m 59s

Provide feedback