Sync up deleted branches & action assets related cleanup documentation (#31022) (#31049)

Backport #31022 by @kemzeb

Syncs up docs associated to actions and deleted branch cleanup i.e. in
custom/app.example.ini and the config cheat sheet.

Co-authored-by: Kemal Zebari <60799661+kemzeb@users.noreply.github.com>

custom/conf/app.example.ini

@@ -2035,6 +2035,17 @@ LEVEL = Info
 ;;   or only create new users if UPDATE_EXISTING is set to false
 ;UPDATE_EXISTING = true
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;; Cleanup expired actions assets
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;[cron.cleanup_actions]
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;ENABLED = true
+;RUN_AT_START = true
+;SCHEDULE = @midnight
+
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Clean-up deleted branches

docs/content/administration/config-cheat-sheet.en-us.md

@@ -974,12 +974,20 @@ Default templates for project boards:
 - `SCHEDULE`: **@midnight** : Interval as a duration between each synchronization, it will always attempt synchronization when the instance starts.
 - `UPDATE_EXISTING`: **true**: Create new users, update existing user data and disable users that are not in external source anymore (default) or only create new users if UPDATE_EXISTING is set to false.
 
-## Cron - Cleanup Expired Actions Assets (`cron.cleanup_actions`)
+#### Cron - Cleanup Expired Actions Assets (`cron.cleanup_actions`)
 
 - `ENABLED`: **true**: Enable cleanup expired actions assets job.
 - `RUN_AT_START`: **true**: Run job at start time (if ENABLED).
 - `SCHEDULE`: **@midnight** : Cron syntax for the job.
 
+#### Cron - Cleanup Deleted Branches (`cron.deleted_branches_cleanup`)
+
+- `ENABLED`: **true**: Enable deleted branches cleanup.
+- `RUN_AT_START`: **true**: Run job at start time (if ENABLED).
+- `NOTICE_ON_SUCCESS`: **false**: Set to true to log a success message.
+- `SCHEDULE`: **@midnight**: Cron syntax for scheduling deleted branches cleanup.
+- `OLDER_THAN`: **24h**: Branches deleted OLDER_THAN ago will be cleaned up.
+
 ### Extended cron tasks (not enabled by default)
 
 #### Cron - Garbage collect all repositories (`cron.git_gc_repos`)