message: Fix programmatic querying example
diff: @@ -53,7 +53,7 @@ public:
  unique_ptr<BoundFunctionExpression> resolve_function(Connection &con, string name, vector<SQLType> function_args,
  bool is_operator = true) {
  auto catalog_entry =
  - con.context->catalog.GetFunction(con.context->transaction.ActiveTransaction(), DEFAULT_SCHEMA, name, false);
  + con.context->catalog.GetEntry(*con.context, CatalogType::SCALAR_FUNCTION, DEFAULT_SCHEMA, name, false);
  assert(catalog_entry->type == CatalogType::SCALAR_FUNCTION);
  auto scalar_fun = (ScalarFunctionCatalogEntry *)catalog_entry;
  @@ -65,7 +65,7 @@ unique_ptr<BoundFunctionExpression> resolve_function(Connection &con, string nam
  unique_ptr<BoundAggregateExpression> resolve_aggregate(Connection &con, string name, vector<SQLType> function_args) {
  auto catalog_entry =
  - con.context->catalog.GetFunction(con.context->transaction.ActiveTransaction(), DEFAULT_SCHEMA, name, false);
  + con.context->catalog.GetEntry(*con.context, CatalogType::AGGREGATE_FUNCTION, DEFAULT_SCHEMA, name, false);
  assert(catalog_entry->type == CatalogType::AGGREGATE_FUNCTION);
  auto aggr_fun = (AggregateFunctionCatalogEntry *)catalog_entry;
  @@ -85,9 +85,9 @@ int main() {
  con.context->transaction.SetAutoCommit(false);
  con.context->transaction.BeginTransaction();
  - auto &trans = con.context->transaction.ActiveTransaction();
  + auto &context = *con.context;
  - con.context->catalog.CreateTableFunction(trans, &info);
  + con.context->catalog.CreateTableFunction(*con.context, &info);
  // use sql for everything
  auto result = con.Query("SELECT (some_int + 42) % 2, count(*) FROM my_scan() WHERE some_int BETWEEN 3 AND 7 group "
  @@ -112,8 +112,7 @@ int main() {
  // TABLE_FUNCTION my_scan
  vector<unique_ptr<ParsedExpression>> children; // empty
  - FunctionExpression fun_expr(DEFAULT_SCHEMA, "my_scan", children);
  - auto scan_function_catalog_entry = con.context->catalog.GetTableFunction(trans, &fun_expr);
  + auto scan_function_catalog_entry = con.context->catalog.GetEntry<TableFunctionCatalogEntry>(*con.context, DEFAULT_SCHEMA, "my_scan");
  vector<unique_ptr<Expression>> parameters; // empty
  auto scan_function = make_unique<PhysicalTableFunction>(types, scan_function_catalog_entry, move(parameters));
  