DOCSP-33300: Fix aggregation operator links to the manual (#448)

(cherry picked from commit a3e5a70)

Author: Chris Cho

source/fundamentals/aggregation-expression-operations.txt

@@ -311,13 +311,13 @@ using the methods described in this section.
      - :manual:`$filter </reference/operator/aggregation/filter/>`
 
    * - `first() <{+api+}/apidocs/mongodb-driver-core/com/mongodb/client/model/mql/MqlArray.html#first()>`__
-     - :manual:`$first </reference/operator/aggregation/first-array-element/>`
+     - :manual:`$first </reference/operator/aggregation/first/>`
 
    * - `joinStrings() <{+api+}/apidocs/mongodb-driver-core/com/mongodb/client/model/mql/MqlArray.html#joinStrings(java.util.function.Function)>`__
      - :manual:`$concat </reference/operator/aggregation/concat/>`
 
    * - `last() <{+api+}/apidocs/mongodb-driver-core/com/mongodb/client/model/mql/MqlArray.html#last()>`__
-     - :manual:`$last </reference/operator/aggregation/last-array-element/>`
+     - :manual:`$last </reference/operator/aggregation/last/>`
 
    * - `map() <{+api+}/apidocs/mongodb-driver-core/com/mongodb/client/model/mql/MqlArray.html#map(java.util.function.Function)>`__
      - :manual:`$map </reference/operator/aggregation/map/>`