DOCSP-46235: Add links to LINQ in API docs (#441)

* DOCSP-46235: Add links to LINQ in API docs

* MW feedback

(cherry picked from commit 997fa8c)

Author: mcmorisi

source/fundamentals/linq.txt

@@ -1031,3 +1031,11 @@ uses a scalar operation, then prints the translated query:
    ``LoggedStages`` is not thread-safe. Executing a query and accessing the
    associated ``LoggedStages`` property from multiple threads might have
    non-deterministic results.
+
+API Documentation
+-----------------
+
+For a complete list of supported LINQ methods, see the following API documentation:
+
+- `LINQ <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.Linq.html>`__
+- `MongoQueryable <{+new-api-root+}/MongoDB.Driver/MongoDB.Driver.Linq.MongoQueryable.html>`__