Effect is a keywork on OCaml 5.3. #11861

Job	Run time
build_details	3s
build_opam (4.14.x)	8m 54s
build_js	2m 10s
build_opam (5.2.x)	5m 13s
build_no_depopts	5m 27s
lezer_parse	51s
tree_sitter_parse	52s
build_win32 (x64)	17m 59s
update_doc	10m 40s
run_tests (@citest)	12m 29s
build_posix (debian_trixie, amd64)	14m 15s
run_tests (@doctest)	7m 18s
build_posix (debian_trixie, arm64)	13m 3s
run_tests (@mediatest)	11m 50s
build_posix (debian_bookworm, amd64)	14m 2s
build_posix (debian_bookworm, arm64)	12m 51s
build_posix (ubuntu_oracular, amd64)	13m 21s
build_posix (ubuntu_oracular, arm64)	12m 51s
build_posix (ubuntu_noble, amd64)	13m 26s
build_posix (ubuntu_noble, arm64)	12m 0s
build_posix (alpine, amd64)	9m 44s
build_posix (alpine, arm64)	8m 11s
fetch_s3_artifacts	22s
build_docker (amd64)	2m 35s
build_docker (arm64)	3m 1s
build_docker_minimal	0s
build_docker_alpine	0s
build_docker_alpine_minimal	0s
build_docker_release-minimal	0s
update_release	0s
build_docker_release	0s
	3h 33m 28s

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