Emit Bonded event when rebonding (#9040)

* Emit `Bonded` event when rebonding

* fix borrow checker

* cargo run --release --features=runtime-benchmarks --manifest-path=bin/node/cli/Cargo.toml -- benchmark --chain=dev --steps=50 --repeat=20 --pallet=pallet_staking --extrinsic=* --execution=wasm --wasm-execution=compiled --heap-pages=4096 --output=./frame/staking/src/weights.rs --template=./.maintain/frame-weight-template.hbs

Co-authored-by: Parity Bot <admin@parity.io>

Author: shawntabrizi

frame/staking/src/lib.rs

@@ -1822,6 +1822,7 @@ decl_module! {
 			// last check: the new active amount of ledger must be more than ED.
 			ensure!(ledger.active >= T::Currency::minimum_balance(), Error::<T>::InsufficientValue);
 
+			Self::deposit_event(RawEvent::Bonded(ledger.stash.clone(), value));
 			Self::update_ledger(&controller, &ledger);
 			Ok(Some(
 				35 * WEIGHT_PER_MICROS