Update manpage for Python 3

Update manpage dependencies list for compatibility with Python 3.

man/xdgmenumaker.t2t

@@ -31,7 +31,9 @@ according to the running user locale settings.
 //compizboxmenu//, //fluxbox//, //icewm//, //jwm//, //pekwm// and
 //windowmaker//.
 
-pyxdg and pygtk are required by **xdgmenumaker**, in addition to python 2.
+**xdgmenumaker** requires //Python 2.7// or //3.x//, //pygtk//
+(for Python 2.7) or //pygobject// and //gobject-instrospection//
+(for Python 3.x), as well as //pyxdg//.
 
 
 = OPTIONS =