chore(blocksync): improve err message (cometbft#2872)

Closes cometbft#2871

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#### PR checklist

- [ ] ~~Tests written/updated~~
- [ ] ~~Changelog entry added in `.changelog` (we use
[unclog](https://github.com/informalsystems/unclog) to manage our
changelog)~~
- [ ] ~~Updated relevant documentation (`docs/` or `spec/`) and code
comments~~
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Co-authored-by: Andy Nogueira <me@andynogueira.dev>

internal/blocksync/reactor.go

@@ -496,7 +496,7 @@ FOR_LOOP:
 				}
 			}
 			if err != nil {
-				bcR.Logger.Error("Error in validation", "err", err)
+				bcR.Logger.Error("Invalid block", "height", first.Height, "err", err)
 				peerID := bcR.pool.RemovePeerAndRedoAllPeerRequests(first.Height)
 				peer := bcR.Switch.Peers().Get(peerID)
 				if peer != nil {

state/validation.go

@@ -54,7 +54,7 @@ func validateBlock(state State, block *types.Block) error {
 
 	// Validate app info
 	if !bytes.Equal(block.AppHash, state.AppHash) {
-		return fmt.Errorf("wrong Block.Header.AppHash.  Expected %X, got %v",
+		return fmt.Errorf("wrong Block.Header.AppHash.  Expected %X, got %v. Check ABCI app for non-determinism",
 			state.AppHash,
 			block.AppHash,
 		)