update both core and ml docs (onnx#1879)

Author: houseroad

tools/update_doc.sh

@@ -25,5 +25,6 @@ python onnx/backend/test/stat_coverage.py
 
 echo -e "\n===> regenerate the docs"
 python onnx/defs/gen_doc.py
+ONNX_ML=0 python onnx/defs/gen_doc.py
 
 echo -e "\n===> the update is done!"