Update batch.md (#1552)

Add two missing available parameters for watcher.py (used with docker):
- OCR_LOGLEVEL
- OCR_JSON_SETTINGS

docs/batch.md

@@ -196,6 +196,10 @@ it to a OCRed PDF in `/output/`, and move the processed original to
   - Define environment variable `OCR_DESKEW` to apply deskew to crooked input PDFs
 * - `--env PYTHONBUFFERED=1`
   - This will force `STDOUT` to be unbuffered and allow you to see messages in docker logs
+* - `--env OCR_LOGLEVEL='DEBUG'`
+  - Level of log messages
+* - `--env OCR_JSON_SETTINGS={"language":"deu+eng", "rotate_pages": true}`
+  - A JSON string specifying any other arguments for `ocrmypdf.ocr`
 :::
 
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