[doc] Allow copying as curl for saved object rollback instructions (e…

…lastic#200187)

## Summary

Changed the doc file so it allows to copy as curl.

[Issue](elastic#198490)

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

docs/setup/upgrade/rollback-migration.asciidoc

@@ -20,7 +20,7 @@ To roll back after a failed upgrade migration, you must also roll back the {kib}
 . To make sure no {kib} instances are performing an upgrade migration, shut down all {kib} instances.
 . {ref}/snapshots-restore-snapshot.html[Restore] the `kibana` feature state from a snapshot taken before the failed {kib} upgrade. The following {es} request will only restore the {kib} feature state 
 +
-[source,sh]
+[source,console]
 --------------------------------------------
 POST _snapshot/my_repository/my_snapshot_2099.05.06/_restore
 {