Remove klaytn from ecrecover error

.github/PULL_REQUEST_TEMPLATE.md

@@ -13,10 +13,10 @@ Please put an x in the boxes related to your change.
 
 ## Checklist
 
-*Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.*
+_Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code._
 
-- [ ] I have read the [ ] I have read the [CONTRIBUTING GUIDELINES](https://github.com/kaiachain/kaia/blob/main/CONTRIBUTING.md) doc
-- [ ] I have read the [CLA](https://gist.github.com/kaiachain-dev/bbf65cc330275c057463c4c94ce787a6) and signed by comment ```I have read the CLA Document and I hereby sign the CLA``` in first time contribute
+- [ ] I have read the [CONTRIBUTING GUIDELINES](https://github.com/kaiachain/kaia/blob/main/CONTRIBUTING.md) doc
+- [ ] I have read the [CLA](https://gist.github.com/kaiachain-dev/bbf65cc330275c057463c4c94ce787a6) and signed by comment `I have read the CLA Document and I hereby sign the CLA` in first time contribute
 - [ ] Lint and unit tests pass locally with my changes (`$ make test`)
 - [ ] I have added tests that prove my fix is effective or that my feature works
 - [ ] I have added necessary documentation (if appropriate)

api/api_private_account.go

@@ -492,7 +492,7 @@ func (s *PrivateAccountAPI) EcRecover(ctx context.Context, data, sig hexutil.Byt
 		return common.Address{}, errors.New("signature must be 65 bytes long")
 	}
 	if sig[crypto.RecoveryIDOffset] != 27 && sig[crypto.RecoveryIDOffset] != 28 {
-		return common.Address{}, errors.New("invalid Klaytn signature (V is not 27 or 28)")
+		return common.Address{}, errors.New("invalid signature (V is not 27 or 28)")
 	}
 
 	// Transform yellow paper V from 27/28 to 0/1

api/api_public_transaction_pool.go

@@ -597,10 +597,10 @@ func (s *PublicTransactionPoolAPI) RecoverFromMessage(
 	ctx context.Context, address common.Address, data, sig hexutil.Bytes, blockNumber rpc.BlockNumber,
 ) (common.Address, error) {
 	if len(sig) != crypto.SignatureLength {
-		return common.Address{}, fmt.Errorf("signature must be 65 bytes long")
+		return common.Address{}, errors.New("signature must be 65 bytes long")
 	}
 	if sig[crypto.RecoveryIDOffset] != 27 && sig[crypto.RecoveryIDOffset] != 28 {
-		return common.Address{}, fmt.Errorf("invalid Klaytn signature (V is not 27 or 28)")
+		return common.Address{}, errors.New("invalid signature (V is not 27 or 28)")
 	}
 
 	// Transform yellow paper V from 27/28 to 0/1