Fix doc-test #12698

Job	Run time
android	20s
Format + check + test	5m 34s
Check wasm32 + wasm-bindgen	2m 37s
cargo-deny aarch64-apple-darwin	37s
ios	19s
Check Windows	1m 37s
cargo-deny aarch64-linux-android	39s
cargo-deny i686-pc-windows-gnu	41s
cargo-deny i686-pc-windows-msvc	38s
cargo-deny i686-unknown-linux-gnu	37s
cargo-deny wasm32-unknown-unknown	40s
cargo-deny x86_64-apple-darwin	44s
cargo-deny x86_64-pc-windows-gnu	39s
cargo-deny x86_64-pc-windows-msvc	38s
cargo-deny x86_64-unknown-linux-gnu	40s
cargo-deny x86_64-unknown-linux-musl	37s
cargo-deny x86_64-unknown-redox	38s
	18m 15s

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