Reformat imports to a consistent style for imports

rustfmt.toml configuration:
  imports_granularity = "One"
  group_imports = "One"

core/src/rewards_recorder_service.rs

@@ -1,15 +1,17 @@
-use crossbeam_channel::{Receiver, RecvTimeoutError, Sender};
-use solana_ledger::blockstore::Blockstore;
-use solana_runtime::bank::RewardInfo;
-use solana_sdk::{clock::Slot, pubkey::Pubkey};
-use solana_transaction_status::Reward;
-use std::{
-    sync::{
-        atomic::{AtomicBool, Ordering},
-        Arc,
+use {
+    crossbeam_channel::{Receiver, RecvTimeoutError, Sender},
+    solana_ledger::blockstore::Blockstore,
+    solana_runtime::bank::RewardInfo,
+    solana_sdk::{clock::Slot, pubkey::Pubkey},
+    solana_transaction_status::Reward,
+    std::{
+        sync::{
+            atomic::{AtomicBool, Ordering},
+            Arc,
+        },
+        thread::{self, Builder, JoinHandle},
+        time::Duration,
     },
-    thread::{self, Builder, JoinHandle},
-    time::Duration,
 };
 
 pub type RewardsRecorderReceiver = Receiver<(Slot, Vec<(Pubkey, RewardInfo)>)>;