[DOCS] Fixes incorrect filter data type

Author: lcawl

docs/reference/ml/apis/filterresource.asciidoc

@@ -9,7 +9,7 @@ A filter resource has the following properties:
   (string) A string that uniquely identifies the filter.
 
 `description`::
-  (array) A description of the filter.
+  (string) A description of the filter.
 
 `items`::
   (array of strings) An array of strings which is the filter item list.