docs: fix udev rule priority in automated-local.rst

fixes #8639
The priority of 40 for the udev rules as stated in to documentation
applies the rule too early on some systems, which prevents the rule from
matching. This commit changes the priority to 80.

docs/deployment/automated-local.rst

@@ -32,7 +32,7 @@ All configuration goes into this directory.
 Find out the ID of the partition table of your backup disk (here assumed to be /dev/sdz):
     lsblk --fs -o +PTUUID /dev/sdz
 
-Then, create ``/etc/backups/40-backup.rules`` with the following content (all on one line)::
+Then, create ``/etc/backups/80-backup.rules`` with the following content (all on one line)::
 
     ACTION=="add", SUBSYSTEM=="block", ENV{ID_PART_TABLE_UUID}=="<the PTUUID you just noted>", TAG+="systemd", ENV{SYSTEMD_WANTS}="automatic-backup.service"
 
@@ -164,7 +164,7 @@ The last part is to actually enable the udev rules and services:
 
 .. code-block:: bash
 
-    ln -s /etc/backups/40-backup.rules /etc/udev/rules.d/40-backup.rules
+    ln -s /etc/backups/80-backup.rules /etc/udev/rules.d/80-backup.rules
     ln -s /etc/backups/automatic-backup.service /etc/systemd/system/automatic-backup.service
     systemctl daemon-reload
     udevadm control --reload