Update feature-support-40.md

Author: gahl-levy

articles/cosmos-db/mongodb/feature-support-40.md

@@ -190,6 +190,9 @@ Azure Cosmos DB's API for MongoDB supports the following database commands:
 
 ### Comparison expressions
 
+> [!NOTE]
+> The API for MongoDB does not support comparison expressions for the array data type.
+
 | Command | Supported |
 |---------|---------|
 | $cmp | Yes |