[DOCS] Fixes typo in preview datafeed API (#79863) (#79879)

Author: lcawl

docs/reference/ml/anomaly-detection/apis/preview-datafeed.asciidoc

@@ -25,6 +25,7 @@ Previews a {dfeed}.
 == {api-prereq-title}
 
 Requires the following privileges:
+
 * cluster: `manage_ml` (the `machine_learning_admin` built-in role grants this 
    privilege)
 * source index configured in the {dfeed}: `read`.