`ScanForWalletTransactions()` has the following comment about its return value:

```
 * Returns null if scan was successful. Otherwise, if a complete rescan was not
 * possible (due to pruning or corruption), returns pointer to the most recent
 * block that could not be scanned.
```

This is not strictly true. If `abortrescan` is called, then `ScanForWalletTransactions()` will return `nullptr`, even though the scan wasn't successful to the tip.

This in turn causes a minor bug in `importmulti`, where the call doesn't return the correct error and warning about potentially not finding transactions if `abortrescan` was called.

I think the correct fix is for `ScanForWalletTransactions()` to inform the caller that the rescan was aborted.
{
    
    if (!fBroadcastTransactions)
        return;
    auto locked_chain = chain().lock();
    LOCK(cs_wallet);
    std::map<int64_t, CWalletTx*> mapSorted;
    
    for (std::pair<const uint256, CWalletTx>& item : mapWallet)
    {
        const uint256& wtxid = item.first;
        CWalletTx& wtx = item.second;
        assert(wtx.GetHash() == wtxid);
        int nDepth = wtx.GetDepthInMainChain(*locked_chain);
        if (!wtx.IsCoinBase() && (nDepth == 0 && !wtx.isAbandoned())) {
            mapSorted.insert(std::make_pair(wtx.nOrderPos, &wtx));
        }
    }
    
    for (const std::pair<const int64_t, CWalletTx*>& item : mapSorted) {
        CWalletTx& wtx = *(item.second);
        CValidationState state;
        wtx.AcceptToMemoryPool(*locked_chain, maxTxFee, state);
    }
}
bool CWalletTx::RelayWalletTransaction(interfaces::Chain::Lock& locked_chain, CConnman* connman)