SF bug #844123: "up" instead of "down" in turtle module documentation

Doc/lib/libturtle.tex

@@ -65,7 +65,7 @@ Move the pen up --- stop drawing.
 \end{funcdesc}
 
 \begin{funcdesc}{down}{}
-Move the pen up --- draw when moving.
+Move the pen down --- draw when moving.
 \end{funcdesc}
 
 \begin{funcdesc}{width}{width}