Add state message print to AcceptBlock failure message.

This should make it easier to debug issues where the CheckBlock at
the top of ProcessNewBlock fails (which does not print, in contrast
to AcceptBlock, which always prints).

src/validation.cpp

@@ -3189,7 +3189,7 @@ bool ProcessNewBlock(const CChainParams& chainparams, const std::shared_ptr<cons
         CheckBlockIndex(chainparams.GetConsensus());
         if (!ret) {
             GetMainSignals().BlockChecked(*pblock, state);
-            return error("%s: AcceptBlock FAILED", __func__);
+            return error("%s: AcceptBlock FAILED (%s)", __func__, state.GetDebugMessage());
         }
     }