Update requirements.txt

requirements.txt

@@ -5,4 +5,12 @@ language-tool-python
 tqdm
 flask
 pymupdf4llm == 0.0.17
-mdit_plain
+mdit_plain
+span_marker
+# span_marker typically depends on transformers and a backend like torch or tensorflow.
+# Pip should resolve these, but explicitly listing them can be helpful.
+# Check span_marker documentation for specific compatible versions if issues arise.
+transformers 
+torch 
+# If you prefer tensorflow, ensure it's installed and span_marker uses it.
+# tensorflow