move generics of election trait to associated types (#10475)

* move generics of election trait to associated types

* fix doctest

substrate/frame/staking/src/pallet/impls.rs

@@ -844,7 +844,9 @@ impl<T: Config> Pallet<T> {
 	}
 }
 
-impl<T: Config> ElectionDataProvider<T::AccountId, BlockNumberFor<T>> for Pallet<T> {
+impl<T: Config> ElectionDataProvider for Pallet<T> {
+	type AccountId = T::AccountId;
+	type BlockNumber = BlockNumberFor<T>;
 	const MAXIMUM_VOTES_PER_VOTER: u32 = T::MAX_NOMINATIONS;
 
 	fn desired_targets() -> data_provider::Result<u32> {

substrate/frame/staking/src/pallet/mod.rs

@@ -79,16 +79,16 @@ pub mod pallet {
 
 		/// Something that provides the election functionality.
 		type ElectionProvider: frame_election_provider_support::ElectionProvider<
-			Self::AccountId,
-			Self::BlockNumber,
+			AccountId = Self::AccountId,
+			BlockNumber = Self::BlockNumber,
 			// we only accept an election provider that has staking as data provider.
 			DataProvider = Pallet<Self>,
 		>;
 
 		/// Something that provides the election functionality at genesis.
 		type GenesisElectionProvider: frame_election_provider_support::ElectionProvider<
-			Self::AccountId,
-			Self::BlockNumber,
+			AccountId = Self::AccountId,
+			BlockNumber = Self::BlockNumber,
 			DataProvider = Pallet<Self>,
 		>;