Fix ambiguous lifetimes #363

Job	Run time
Audit	12s
cargo clippy	23s
cargo fmt	11s
Build with no-std on wasm32-unknown-unknown	19s
Taplo	9s
Build with no-std on wasm32-unknown-unknown	13s
test (--features ristretto255-ciphersuite, stable)	55s
Build with no-std on wasm32-unknown-unknown	16s
test (--features ristretto255-ciphersuite, 1.65.0)	2m 55s
Build with no-std on wasm32-unknown-unknown	12s
test (--features ristretto255-ciphersuite, --features danger, stable)	1m 28s
Build with no-std on wasm32-unknown-unknown	12s
test (--features ristretto255-ciphersuite, --features danger, 1.65.0)	3m 28s
Build with no-std on wasm32-unknown-unknown	17s
test (--features ristretto255-ciphersuite, --features serde, stable)	1m 33s
Build with no-std on thumbv6m-none-eabi	13s
test (--features ristretto255-ciphersuite, --features serde, 1.65.0)	3m 30s
Build with no-std on thumbv6m-none-eabi	12s
test (stable)	1m 4s
Build with no-std on thumbv6m-none-eabi	15s
test (1.65.0)	3m 3s
Build with no-std on thumbv6m-none-eabi	12s
test (--features danger, stable)	1m 19s
Build with no-std on thumbv6m-none-eabi	20s
test (--features danger, 1.65.0)	3m 25s
Build with no-std on thumbv6m-none-eabi	18s
test (--features serde, stable)	1m 19s
test (--features serde, 1.65.0)	3m 24s
	31m 17s

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