Hint about coercion in error msg #6901

Job	Run time
build-compiler (ubuntu-24.04, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, linux...	13m 55s
build-compiler (ubuntu-24.04-arm, ocaml-variants.5.3.0+options,ocaml-option-static, true, true, t...	11m 40s
build-compiler (macos-13, 5.3.0, true, darwin-x64, x86_64-apple-darwin)	19m 10s
build-compiler (macos-14, 5.3.0, true, darwin-arm64, aarch64-apple-darwin)	11m 46s
build-compiler (windows-latest, 5.3.0, true, win32-x64, x86_64-pc-windows-gnu)	10m 11s
build-compiler (ubuntu-24.04, ocaml-variants.5.2.1+options,ocaml-option-static, linux-x64, x86_64...	12m 12s
build-compiler (ubuntu-24.04, ocaml-variants.5.0.0+options,ocaml-option-static, linux-x64, x86_64...	12m 12s
build-compiler (ubuntu-24.04, ocaml-variants.4.14.2+options,ocaml-option-static, linux-x64, x86_6...	12m 15s
pkg-pr-new	54s
test-integration (macos-13)	31s
test-integration (macos-14)	21s
test-integration (ubuntu-24.04)	40s
test-integration (ubuntu-24.04-arm)	39s
test-integration (windows-latest)	36s
publish	0s
	1h 47m 2s

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