PHPLIB-1192: Remove useCursor option in aggregate (#1130)

* PHPLIB-1192: Remove useCursor option in aggregate

* Remove unnecessary property for isExplain

Author: alcaeus

source/includes/apiargs-MongoDBCollection-method-aggregate-option.yaml

@@ -59,22 +59,6 @@ source:
   file: apiargs-MongoDBCollection-common-option.yaml
   ref: typeMap
 ---
-arg_name: option
-name: useCursor
-type: boolean
-description: |
-  Indicates whether the command will request that the server provide results
-  using a cursor. The default is ``true``.
-
-  .. note::
-
-     MongoDB 3.6+ no longer supports returning results without a cursor (excluding
-     when the explain option is used) and specifying false for this option will
-     result in a server error.
-interface: phpmethod
-operation: ~
-optional: true
----
 source:
   file: apiargs-MongoDBCollection-common-option.yaml
   ref: writeConcern

source/reference/method/MongoDBCollection-aggregate.txt

@@ -50,13 +50,8 @@ Errors/Exceptions
 Behavior
 --------
 
-:phpmethod:`MongoDB\\Collection::aggregate()`'s return value depends on the
-MongoDB server version and whether the ``useCursor`` option is specified. If
-``useCursor`` is ``true``, a :php:`MongoDB\\Driver\\Cursor
-<class.mongodb-driver-cursor>` object is returned. If ``useCursor`` is
-``false``, an :php:`ArrayIterator <arrayiterator>` is returned that wraps the
-``result`` array from the command response document. In both cases, the return
-value will be :php:`Traversable <traversable>`.
+:phpmethod:`MongoDB\\Collection::aggregate()`'s returns a
+:php:`MongoDB\\Driver\\Cursor <class.mongodb-driver-cursor>` object.
 
 Examples
 --------