consensus: fix possessives in comments. (ethereum#20209)

consensus/clique/clique.go

@@ -311,7 +311,7 @@ func (c *Clique) verifyCascadingFields(chain consensus.ChainReader, header *type
 	if number == 0 {
 		return nil
 	}
-	// Ensure that the block's timestamp isn't too close to it's parent
+	// Ensure that the block's timestamp isn't too close to its parent
 	var parent *types.Header
 	if len(parents) > 0 {
 		parent = parents[len(parents)-1]
@@ -522,7 +522,7 @@ func (c *Clique) Prepare(chain consensus.ChainReader, header *types.Header) erro
 	// Set the correct difficulty
 	header.Difficulty = CalcDifficulty(snap, c.signer)
 
-	// Ensure the extra data has all it's components
+	// Ensure the extra data has all its components
 	if len(header.Extra) < extraVanity {
 		header.Extra = append(header.Extra, bytes.Repeat([]byte{0x00}, extraVanity-len(header.Extra))...)
 	}

consensus/errors.go

@@ -31,7 +31,7 @@ var (
 	// to the current node.
 	ErrFutureBlock = errors.New("block in the future")
 
-	// ErrInvalidNumber is returned if a block's number doesn't equal it's parent's
+	// ErrInvalidNumber is returned if a block's number doesn't equal its parent's
 	// plus one.
 	ErrInvalidNumber = errors.New("invalid block number")
 )

consensus/ethash/consensus.go

@@ -86,7 +86,7 @@ func (ethash *Ethash) VerifyHeader(chain consensus.ChainReader, header *types.He
 	if ethash.config.PowMode == ModeFullFake {
 		return nil
 	}
-	// Short circuit if the header is known, or it's parent not
+	// Short circuit if the header is known, or its parent not
 	number := header.Number.Uint64()
 	if chain.GetHeader(header.Hash(), number) != nil {
 		return nil
@@ -252,7 +252,7 @@ func (ethash *Ethash) verifyHeader(chain consensus.ChainReader, header, parent *
 	if header.Time <= parent.Time {
 		return errZeroBlockTime
 	}
-	// Verify the block's difficulty based in it's timestamp and parent's difficulty
+	// Verify the block's difficulty based in its timestamp and parent's difficulty
 	expected := ethash.CalcDifficulty(chain, header.Time, parent)
 
 	if expected.Cmp(header.Difficulty) != 0 {