Update docgen, run on source rather than build directory

cook.sh

@@ -364,7 +364,7 @@ function op {
                     done
                 fi
 
-                docgen . ../stage/ref/
+                docgen ../source ../stage/ref
             fi
             popd > /dev/null
             ;;

docgen @ 67119659

-Subproject commit 52fb8863efdd0862b2439f87faff2457b43cac62
+Subproject commit 67119659a484dba78eb29c1081afc8f8ea7014c3