Debian: Change boot loader step

Instead of a numbered list, these should be alternate options.  This
makes the Debian Bookworm instructions match the Ubuntu 22.04 ones.  I
did not go back further.

Author: rlaager

docs/Getting Started/Debian/Debian Bookworm Root on ZFS.rst

@@ -824,19 +824,21 @@ Step 5: GRUB Installation
 
 #. Install the boot loader:
 
-   #. For legacy (BIOS) booting, install GRUB to the MBR::
+   Choose one of the following options:
+
+   - For legacy (BIOS) booting, install GRUB to the MBR::
 
-        grub-install $DISK
+       grub-install $DISK
 
-      Note that you are installing GRUB to the whole disk, not a partition.
+     Note that you are installing GRUB to the whole disk, not a partition.
 
-      If you are creating a mirror or raidz topology, repeat the ``grub-install``
-      command for each disk in the pool.
+     If you are creating a mirror or raidz topology, repeat the
+     ``grub-install`` command for each disk in the pool.
 
-   #. For UEFI booting, install GRUB to the ESP::
+   - For UEFI booting, install GRUB to the ESP::
 
-        grub-install --target=x86_64-efi --efi-directory=/boot/efi \
-            --bootloader-id=debian --recheck --no-floppy
+       grub-install --target=x86_64-efi --efi-directory=/boot/efi \
+           --bootloader-id=debian --recheck --no-floppy
 
       It is not necessary to specify the disk here. If you are creating a
       mirror or raidz topology, the additional disks will be handled later.