chore: improve codebase with some clippy suggestions (#867) #3075

Job	Run time
Check Documentation	1m 6s
Test (stable)	8m 57s
Test (nightly)	17m 33s
Check no_std	27s
Check (stable)	11s
Check Style	9s
List directories for parallelizing tests	2s
Check (nightly)	1m 2s
Test assembly	8m 19s
Test (cp6_782/)	6s
Test (mnt4_753/)	9m 27s
Test (mnt6_753/)	10s
Test (./ed_on_mnt4_753)	3m 47s
Test (./secp256r1)	1m 3s
Test (./ed_on_mnt4_298)	1m 3s
Test (./ed_on_cp6_782)	1m 22s
Test (./mnt4_298)	3m 48s
Test (./mnt6_298)	5m 17s
Test (./ed_on_bn254)	58s
Test (./bn254)	2m 26s
Test (./secp256k1)	59s
Test (./bw6_761)	3m 47s
Test (./bls12_377)	4m 25s
Test (./grumpkin)	1m 6s
Test (./secp384r1)	1m 17s
Test (./ed_on_bls12_377)	1m 7s
Test (./secq256k1)	56s
Test (./ed25519)	1m 4s
Test (./ed_on_bls12_381)	1m 10s
Test (./ed_on_bw6_761)	38s
Test (./curve25519)	1m 0s
Test (./ed_on_bls12_381_bandersnatch)	1m 0s
Test (./pallas)	1m 17s
Test (./vesta)	1m 3s
Test (./bw6_767)	3m 59s
Test (./bls12_381)	3m 13s
	1h 35m 14s

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