eth: fix comment typo (#18114)

* consensus/clique: fix comment typo

* eth,eth/downloader: fix comment typo

eth/downloader/queue.go

@@ -325,7 +325,7 @@ func (q *queue) Schedule(headers []*types.Header, from uint64) []*types.Header {
 		}
 		// Make sure no duplicate requests are executed
 		if _, ok := q.blockTaskPool[hash]; ok {
-			log.Warn("Header  already scheduled for block fetch", "number", header.Number, "hash", hash)
+			log.Warn("Header already scheduled for block fetch", "number", header.Number, "hash", hash)
 			continue
 		}
 		if _, ok := q.receiptTaskPool[hash]; ok {

eth/handler.go

@@ -658,7 +658,7 @@ func (pm *ProtocolManager) handleMsg(p *peer) error {
 			p.SetHead(trueHead, trueTD)
 
 			// Schedule a sync if above ours. Note, this will not fire a sync for a gap of
-			// a singe block (as the true TD is below the propagated block), however this
+			// a single block (as the true TD is below the propagated block), however this
 			// scenario should easily be covered by the fetcher.
 			currentBlock := pm.blockchain.CurrentBlock()
 			if trueTD.Cmp(pm.blockchain.GetTd(currentBlock.Hash(), currentBlock.NumberU64())) > 0 {