Fix syntax error in Buster version of unattended-upgrades config.

Signed-off-by: Maximilian Wilhelm <max@sdn.clinic>

unattended-upgrades/50unattended-upgrades.Debian.buster

@@ -48,7 +48,7 @@ Unattended-Upgrade::Package-Blacklist {
 	"batman-adv-dkms";
 };
 
-/ This option allows you to control if on a unclean dpkg exit
+// This option allows you to control if on a unclean dpkg exit
 // unattended-upgrades will automatically run 
 //   dpkg --force-confold --configure -a
 // The default is true, to ensure updates keep getting installed