Make `AffineRepr: Neg<Output = Self>` #3136

Job	Run time
List directories for parallelizing tests	4s
Check no_std	24s
Check (stable)	1m 0s
Check (nightly)	1m 0s
Check Documentation	54s
Check Style	10s
Test (stable)	9m 2s
Test assembly	8m 22s
Test (cp6_782/)	38s
Test (nightly)	17m 31s
Test (mnt4_753/)	15m 54s
Test (mnt6_753/)	34m 19s
Test (./secp256k1)	1s
Test (./mnt6_298)	1s
Test (./ed_on_cp6_782)	1s
Test (./ed_on_bn254)	30s
Test (./secp384r1)	1s
Test (./ed_on_bls12_377)	42s
Test (./bls12_381)	35s
Test (./grumpkin)	1s
Test (./ed_on_bls12_381)	45s
Test (./curve25519)	40s
Test (./ed_on_mnt4_753)	1s
Test (./ed_on_bls12_381_bandersnatch)	34s
Test (./ed25519)	1s
Test (./bls12_377)	44s
Test (./ed_on_bw6_761)	4s
Test (./ed_on_mnt4_298)	1s
Test (./secp256r1)	1s
Test (./mnt4_298)	1s
Test (./secq256k1)	1s
Test (./pallas)	1s
Test (./bw6_761)	30s
Test (./bw6_767)	32s
Test (./bn254)	40s
Test (./vesta)	1s
	1h 35m 47s

Provide feedback