downloader: fix typos, grammar and formatting (ethereum#32288)

Author: tomasandroil

eth/downloader/downloader.go

@@ -199,7 +199,7 @@ type BlockChain interface {
 	// InsertChain inserts a batch of blocks into the local chain.
 	InsertChain(types.Blocks) (int, error)
 
-	// InterruptInsert whether disables the chain insertion.
+	// InterruptInsert disables or enables chain insertion.
 	InterruptInsert(on bool)
 
 	// InsertReceiptChain inserts a batch of blocks along with their receipts
@@ -513,7 +513,7 @@ func (d *Downloader) syncToHead() (err error) {
 		//
 		// For non-merged networks, if there is a checkpoint available, then calculate
 		// the ancientLimit through that. Otherwise calculate the ancient limit through
-		// the advertised height of the remote peer. This most is mostly a fallback for
+		// the advertised height of the remote peer. This is mostly a fallback for
 		// legacy networks, but should eventually be dropped. TODO(karalabe).
 		//
 		// Beacon sync, use the latest finalized block as the ancient limit
@@ -946,7 +946,7 @@ func (d *Downloader) processSnapSyncContent() error {
 		if !d.committed.Load() {
 			latest := results[len(results)-1].Header
 			// If the height is above the pivot block by 2 sets, it means the pivot
-			// become stale in the network, and it was garbage collected, move to a
+			// became stale in the network, and it was garbage collected, move to a
 			// new pivot.
 			//
 			// Note, we have `reorgProtHeaderDelay` number of blocks withheld, Those
@@ -1043,7 +1043,7 @@ func (d *Downloader) commitSnapSyncData(results []*fetchResult, stateSync *state
 	first, last := results[0].Header, results[len(results)-1].Header
 	log.Debug("Inserting snap-sync blocks", "items", len(results),
 		"firstnum", first.Number, "firsthash", first.Hash(),
-		"lastnumn", last.Number, "lasthash", last.Hash(),
+		"lastnum", last.Number, "lasthash", last.Hash(),
 	)
 	blocks := make([]*types.Block, len(results))
 	receipts := make([]rlp.RawValue, len(results))

eth/downloader/downloader_test.go

@@ -544,7 +544,7 @@ func testMultiProtoSync(t *testing.T, protocol uint, mode SyncMode) {
 	tester.newPeer("peer 68", eth.ETH68, chain.blocks[1:])
 
 	if err := tester.downloader.BeaconSync(mode, chain.blocks[len(chain.blocks)-1].Header(), nil); err != nil {
-		t.Fatalf("failed to start beacon sync: #{err}")
+		t.Fatalf("failed to start beacon sync: %v", err)
 	}
 	select {
 	case <-complete: