"version changed" => "version added" (#6629) (#6708)

* "version changed" => "version added"

* update wording based on server ticket timing

* specific patch versions

Author: MongoCaleb

source/reference/operator/aggregation/documents.txt

@@ -15,7 +15,7 @@ Definition
 
 .. pipeline:: $documents
 
-   .. versionchanged:: 5.1
+   .. versionadded:: 5.1 (*Also available in 5.0.3 and 4.4.9*)
 
    Returns literal documents from input values.