Update call-external-action.md to specify collection must be of supported primitives

Author: adeel2023

content/en/docs/refguide/modeling/application-logic/microflows-and-nanoflows/activities/integration-activities/call-external-action.md

@@ -87,7 +87,7 @@ The ability to add additional attributes was introduced in [Studio Pro 11.5.0](/
 
 ### Collection Attributes {#collection-attributes}
 
-When assigning a value to an entity type parameter that has collection attributes (e.g., a list of strings), select the corresponding attribute of matching type from list variable (list of objects) — Mendix will automatically use the whole list to populate the collection values.
+When assigning a value to an entity type parameter that has collection attributes (mendix supported primitive-types; e.g., a list of strings), select the corresponding attribute of matching type from list variable (list of objects) — Mendix will automatically use the whole list to populate the collection values.
 
 {{% alert color="info" %}}
 The support for OData actions with parameter entity type having Collection attribute(s) of supported primitive types, was introduced in [Studio Pro 11.6.0](/releasenotes/studio-pro/11.6/).