Fix typo: Optimizaton -> Optimization

src/versionbits.cpp

@@ -25,7 +25,7 @@ ThresholdState AbstractThresholdConditionChecker::GetStateFor(const CBlockIndex*
             break;
         }
         if (pindexPrev->GetMedianTimePast() < nTimeStart) {
-            // Optimizaton: don't recompute down further, as we know every earlier block will be before the start time
+            // Optimization: don't recompute down further, as we know every earlier block will be before the start time
             cache[pindexPrev] = THRESHOLD_DEFINED;
             break;
         }