Update migration instructions for version-level immutability

Clarified the text regarding container migration and WORM policy.

Author: vgs-msft

articles/storage/blobs/immutable-policy-configure-version-scope.md

@@ -147,7 +147,7 @@ If version-level immutability support is enabled for a container and the contain
 
 #### Migrate an existing container to support version-level immutability
 
-To configure version-level immutability policies for an existing container, you must migrate the container to support version-level immutable storage. Container migration may take some time and can't be reversed. However, if a migration fails, it will revert back to a Container Level WORM container, and you will have to start the migration again. You can migrate 10 containers at a time per storage account.
+To configure version-level immutability policies for an existing container, you must migrate the container to support version-level immutable storage. Container migration may take some time and can't be reversed. However, if a migration fails, it will revert back to a container-level WORM policy, and you will have to start the migration again. You can migrate 10 containers at a time per storage account.
 
 To migrate an existing container to support version-level immutability policies, the container must have a container-level time-based retention policy configured and versioning enabled at the account level. The migration fails unless the container has an existing policy. The retention interval for the container-level policy is maintained as the retention interval for the default version-level policy on the container.