Update alias.asciidoc

Author: mimol91

docs/reference/alias.asciidoc

@@ -84,6 +84,27 @@ POST _aliases
   ]
 }
 ----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\n/]
+
+[discrete]
+[[remove-index]]
+=== Remove an index
+
+To remove an index, use the aliases API's `remove_index` action.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "remove_index": {
+        "index": "logs-nginx.access-prod"
+      }
+    }
+  ]
+}
+----
 // TEST[continued]
 
 [discrete]