message: Fix C API example
diff: @@ -27,13 +27,15 @@ int main() {
  goto cleanup;
  }
  // print the names of the result
  - for (size_t i = 0; i < result.column_count; i++) {
  - printf("%s ", result.columns[i].name);
  + idx_t row_count = duckdb_row_count(&result);
  + idx_t column_count = duckdb_column_count(&result);
  + for (size_t i = 0; i < column_count; i++) {
  + printf("%s ", duckdb_column_name(&result, i));
  }
  printf("\n");
  // print the data of the result
  - for (size_t row_idx = 0; row_idx < result.row_count; row_idx++) {
  - for (size_t col_idx = 0; col_idx < result.column_count; col_idx++) {
  + for (size_t row_idx = 0; row_idx < row_count; row_idx++) {
  + for (size_t col_idx = 0; col_idx < column_count; col_idx++) {
  char *val = duckdb_value_varchar(&result, col_idx, row_idx);
  printf("%s ", val);
  duckdb_free(val);
  