signer/core: show helptext when clef rejects signing (ethereum#27538)

 Co-authored-by: Martin Holst Swende <martin@swende.se>

Author: joohhnnn

signer/core/api.go

@@ -553,6 +553,7 @@ func (api *SignerAPI) SignTransaction(ctx context.Context, args apitypes.SendTxA
 // If we are in 'rejectMode', then reject rather than show the user warnings
 if api.rejectMode {
 if err := msgs.GetWarnings(); err != nil {
+log.Info("Signing aborted due to warnings. In order to continue despite warnings, please use the flag '--advanced'.")
 return nil, err
 }
 }
@@ -625,6 +626,7 @@ func (api *SignerAPI) SignGnosisSafeTx(ctx context.Context, signerAddress common
 // If we are in 'rejectMode', then reject rather than show the user warnings
 if api.rejectMode {
 if err := msgs.GetWarnings(); err != nil {
+log.Info("Signing aborted due to warnings. In order to continue despite warnings, please use the flag '--advanced'.")
 return nil, err
 }
 }