DOCSP-22639 wrong fieldname (#1102)

Author: Dave

source/reference/operator/aggregation/lookup.txt

@@ -539,8 +539,8 @@ Create another collection ``members`` with these documents:
    ] )
 
 The following aggregation operation joins documents in the ``classes``
-collection with the ``members`` collection, matching on the ``members``
-field to the ``name`` field:
+collection with the ``members`` collection, matching on the
+``enrollmentlist`` field to the ``name`` field:
 
 .. code-block:: javascript