Add missing parenthesis

Removed by mistake

src/xdgmenumaker

@@ -200,7 +200,7 @@ def usage():
     print()
     print('OPTIONS:')
     print('    -f, --format         the output format to use.')
-    print('                         Valid options are blackbox, compizboxmenu,'
+    print('                         Valid options are blackbox, compizboxmenu,')
     print('                         fluxbox, icewm, jwm, windowmaker and pekwm')
     print('    -i, --icons          enable support for icons in the')
     print('                         menus. Does not work with windowmaker')