SERVER-42654 add TODO to the place to change FCV

Author: Misha Tyulenev

src/mongo/db/s/config/sharding_catalog_manager_add_shard_test.cpp

@@ -138,6 +138,7 @@ class AddShardTest : public ConfigServerTestFixture {
         });
     }
 
+    // TODO: SERVER-42654
     void expectSetFeatureCompatibilityVersion(const HostAndPort& target,
                                               StatusWith<BSONObj> response,
                                               BSONObj writeConcern) {

src/mongo/db/s/sharding_state_recovery.cpp

@@ -148,8 +148,6 @@ Status modifyRecoveryDocument(OperationContext* opCtx,
         autoGetOrCreateDb.emplace(
             opCtx, NamespaceString::kServerConfigurationNamespace.db(), MODE_X);
 
-        // The config server connection string and shard name are no longer parsed in 4.0, but 3.6
-        // nodes still expect to find them, so we must include them until after 4.0 ships.
         auto const grid = Grid::get(opCtx);
         BSONObj updateObj = RecoveryDocument::createChangeObj(grid->configOpTime(), change);