Add Protocol::SUB/SUB_ASSIGN to Instant #1862

Job	Run time
msrv	1m 42s
clippy	2m 6s
nightly	4m 59s
docs	3m 28s
rustfmt	11s
basics	1s
no_std (ubuntu-latest, minimal)	1m 23s
build_feature (alloc)	3m 39s
no_std (macos-latest, minimal)	1m 23s
test_lib	4m 33s
test_doc	6m 14s
build_feature (cli)	4m 5s
build_feature (cli,doc)	4m 5s
test_rune	3m 13s
test_miri (rune)	3m 49s
build_feature (cli,fmt)	4m 7s
wasm	1m 15s
test_miri (rune-core)	57s
build_feature (doc)	3m 54s
test_miri (rune-alloc)	6m 17s
build_feature (workspace)	3m 42s
build_feature (languageserver)	4m 21s
build_feature (byte-code)	3m 33s
build_feature (capture-io)	3m 22s
build_feature (emit)	3m 31s
	1h 19m 50s

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