[DOCS] Unregister repository instead of deleting it (#29206)

Relates to #15426

Author: ywelsch

docs/reference/modules/snapshots.asciidoc

@@ -401,7 +401,7 @@ created the snapshotting process will be aborted and all files created as part o
 cleaned. Therefore, the delete snapshot operation can be used to cancel long running snapshot operations that were
 started by mistake.
 
-A repository can be deleted using the following command:
+A repository can be unregistered using the following command:
 
 [source,sh]
 -----------------------------------
@@ -410,7 +410,7 @@ DELETE /_snapshot/my_fs_backup
 // CONSOLE
 // TEST[continued]
 
-When a repository is deleted, Elasticsearch only removes the reference to the location where the repository is storing
+When a repository is unregistered, Elasticsearch only removes the reference to the location where the repository is storing
 the snapshots. The snapshots themselves are left untouched and in place.
 
 [float]