eth: fixed typo (#16274)

eth/fetcher/fetcher.go

@@ -633,7 +633,7 @@ func (f *Fetcher) enqueue(peer string, block *types.Block) {
 }
 
 // insert spawns a new goroutine to run a block insertion into the chain. If the
-// block's number is at the same height as the current import phase, if updates
+// block's number is at the same height as the current import phase, it updates
 // the phase states accordingly.
 func (f *Fetcher) insert(peer string, block *types.Block) {
 	hash := block.Hash()