DOCSP-11905 updates ObjectId entry in reference glossary

Author: jmd-mongo

source/reference/glossary.txt

@@ -580,11 +580,13 @@ Glossary
       See :term:`natural order`.
 
    ObjectId
-      A special 12-byte :term:`BSON` type that guarantees uniqueness
-      within the :term:`collection`. The ObjectId is generated based on
-      timestamp, machine ID, process ID, and a process-local incremental
-      counter. MongoDB uses ObjectId values as the default values for
-      :term:`_id` fields.
+      A special :term:`BSON` type that guarantees uniqueness within the 
+      :term:`collection`. :ref:`objectid` values are 12 bytes in length, 
+      consisting of: 
+
+      .. include:: /includes/fact-ObjectId-construct.rst
+
+      See :ref:`document-bson-type-object-id` for BSON-specific information.
 
    operator
       A keyword beginning with a ``$`` used to express an update,