DOCSP-33143-positional-note-v4.4 (#5045)

Co-authored-by: jason-price-mongodb <[email protected]>

Author: jason-price-mongodb

source/reference/operator/update/positional-filtered.txt

@@ -433,6 +433,12 @@ The following updates the values that are greater than or equal to
       { arrayFilters: [ { "t.type": "quiz" } , { "score": { $gte: 8 } } ], multi: true}
    )
 
+.. note::
+
+   Don't add spaces around the array identifiers. If you use
+   ``grades.$[ t ].questions.$[ score ]`` in the previous example, the
+   example fails.
+
 After the operation, the collection has the following document:
 
 .. code-block:: javascript