Add ALTO output for PERO OCR

scripts/combine_tesseract_with_pero_ocr_docker.py

@@ -31,7 +31,7 @@ def main() -> None:
                 (OUTPUT_PATH / pero_ocr_filename.stem).with_suffix(f'.{suffix}'),
             )
 
-        for suffix in ('xml', ):
+        for suffix in ('xml', 'alto'):
             shutil.copy(
                 (PERO_OCR_PATH / pero_ocr_filename.stem).with_suffix(f'.{suffix}'),
                 (OUTPUT_PATH / pero_ocr_filename.stem).with_suffix(f'.{suffix}'),