type crypto/internal/edwards25519.fiatScalarInt1

one use

	crypto/internal/edwards25519 (current package)
		scalar_fiat.go#L44: type fiatScalarInt1 int64   // We use uint64 instead of a more narrow type for performance reasons; see https://github.com/mit-plv/fiat-crypto/pull/1006#issuecomment-892625927