Update 7.9-to-7.10.md

doc/update/7.9-to-7.10.md

@@ -106,7 +106,7 @@ only contains a root URL (ex. `https://gitlab.example.com/`)
 ## Things went south? Revert to previous version (7.9)
 
 ### 1. Revert the code to the previous version
-Follow the [upgrade guide from 7.8 to 7.8](7.8-to-7.9.md), except for the database migration
+Follow the [upgrade guide from 7.8 to 7.9](7.8-to-7.9.md), except for the database migration
 (The backup is already migrated to the previous version)
 
 ### 2. Restore from the backup: