Add 'see also' link to curses.panel

Doc/lib/libcurses.tex

@@ -24,6 +24,8 @@ open-source curses library hosted on Linux and the BSD variants of
   \seemodule{curses.ascii}{Utilities for working with \ASCII{}
                            characters, regardless of your locale
                            settings.}
+  \seemodule{curses.panel}{A panel stack extension that adds depth to 
+                           curses windows.}
   \seemodule{curses.textpad}{Editable text widget for curses supporting 
 			     \program{Emacs}-like bindings.}
   \seemodule{curses.wrapper}{Convenience function to ensure proper