grub/grub_void.cfg.in: add missing ')' that broke configuration.

grub/grub_void.cfg.in

@@ -13,7 +13,7 @@ fi
 
 insmod font
 
-if loadfont "(${voidlive}/boot/grub/fonts/unicode.pf2" ; then
+if loadfont "(${voidlive})/boot/grub/fonts/unicode.pf2" ; then
     insmod gfxterm
     set gfxmode="auto"