use prompt designation for the root account in install message

grub.install

@@ -13,8 +13,8 @@ post_upgrade() {
    to install it to the MBR or UEFI. Due to potential configuration
    incompatibilities, it is advised to run both, installation and generation
    of configuration:
-     \$ grub-install ...
-     \$ grub-mkconfig -o /boot/grub/grub.cfg
+     # grub-install ...
+     # grub-mkconfig -o /boot/grub/grub.cfg
 EOM
 
   # return if old package version greater 2:2.06-0...
@@ -32,7 +32,7 @@ EOM
 post_install() {
   cat <<EOM
 :: Install your bootloader and generate configuration with:
-     \$ grub-install ...
-     \$ grub-mkconfig -o /boot/grub/grub.cfg
+     # grub-install ...
+     # grub-mkconfig -o /boot/grub/grub.cfg
 EOM
 }