Fix wrong-result bug. Previously it could incorrectly report Commit

Blog post forthcoming

ConflictSet.cpp

@@ -2935,8 +2935,7 @@ void fixupMaxVersion(Node *node, WriteContext *writeContext) {
   } break;
   case Type_Node256: {
     auto *self256 = static_cast<Node256 *>(node);
-    max = std::max(
-        max, horizontalMax16(self256->childMaxVersion, writeContext->zero));
+    max = std::max(max, horizontalMax16(self256->maxOfMax, writeContext->zero));
   } break;
   default:                   // GCOVR_EXCL_LINE
     __builtin_unreachable(); // GCOVR_EXCL_LINE