eth/downloader: minor typo fixes in comments (ethereum#21035)

Author: gballet

eth/downloader/downloader_test.go

@@ -1347,7 +1347,7 @@ func testBlockHeaderAttackerDropping(t *testing.T, protocol int) {
 	defer tester.terminate()
 
 	for i, tt := range tests {
-		// Register a new peer and ensure it's presence
+		// Register a new peer and ensure its presence
 		id := fmt.Sprintf("test %d", i)
 		if err := tester.newPeer(id, protocol, []common.Hash{tester.genesis.Hash()}, nil, nil, nil); err != nil {
 			t.Fatalf("test %d: failed to register new peer: %v", i, err)

eth/downloader/queue.go

@@ -235,8 +235,7 @@ func (q *queue) ShouldThrottleReceipts() bool {
 }
 
 // resultSlots calculates the number of results slots available for requests
-// whilst adhering to both the item and the memory limit too of the results
-// cache.
+// whilst adhering to both the item and the memory limits of the result cache.
 func (q *queue) resultSlots(pendPool map[string]*fetchRequest, donePool map[common.Hash]struct{}) int {
 	// Calculate the maximum length capped by the memory limit
 	limit := len(q.resultCache)
@@ -349,7 +348,7 @@ func (q *queue) Schedule(headers []*types.Header, from uint64) []*types.Header {
 }
 
 // Results retrieves and permanently removes a batch of fetch results from
-// the cache. the result slice will be empty if the queue has been closed.
+// the cache. The result slice will be empty if the queue has been closed.
 func (q *queue) Results(block bool) []*fetchResult {
 	q.lock.Lock()
 	defer q.lock.Unlock()