Cleanup our sort usage (#6754)

substrate/frame/staking/src/lib.rs

@@ -1238,12 +1238,12 @@ decl_storage! {
 decl_event!(
 	pub enum Event<T> where Balance = BalanceOf<T>, <T as frame_system::Trait>::AccountId {
 		/// The era payout has been set; the first balance is the validator-payout; the second is
-		/// the remainder from the maximum amount of reward. 
+		/// the remainder from the maximum amount of reward.
 		/// [era_index, validator_payout, remainder]
 		EraPayout(EraIndex, Balance, Balance),
 		/// The staker has been rewarded by this amount. [stash, amount]
 		Reward(AccountId, Balance),
-		/// One validator (and its nominators) has been slashed by the given amount. 
+		/// One validator (and its nominators) has been slashed by the given amount.
 		/// [validator, amount]
 		Slash(AccountId, Balance),
 		/// An old slashing report from a prior era was discarded because it could
@@ -2889,7 +2889,7 @@ impl<T: Trait> Module<T> {
 				let mut exposure_clipped = exposure;
 				let clipped_max_len = T::MaxNominatorRewardedPerValidator::get() as usize;
 				if exposure_clipped.others.len() > clipped_max_len {
-					exposure_clipped.others.sort_unstable_by(|a, b| a.value.cmp(&b.value).reverse());
+					exposure_clipped.others.sort_by(|a, b| a.value.cmp(&b.value).reverse());
 					exposure_clipped.others.truncate(clipped_max_len);
 				}
 				<ErasStakersClipped<T>>::insert(&current_era, &stash, exposure_clipped);