Fix typo in script name to retriev backups

Guides/backup.md

@@ -63,7 +63,7 @@ On local machine
 ```sh
 cd /home/jovian/GitWork/DricomDragon/JovianLinux/ServerScripts/Backup/ ;
 git pull ;
-./j7retrieve
+./j7backretrieve
 ```
 
 ### Enable websites