DOCSP-17445 updated FAQ (#132)

* updated Discriminator FAQ

Author: kyuan-mongodb

source/faq.txt

@@ -96,15 +96,19 @@ Yes, by using a discriminator.
 What is a discriminator?
 ~~~~~~~~~~~~~~~~~~~~~~~~
 
-A discriminator is for cases where you want to use inheritance, and
-store multiple types of documents within the same collection or parent
-document (in case you embed sub-documents). 
+A discriminator is a property that identifies a specific document
+schema. You can use it for inheritance and storing multiple types of
+documents within the same collection or parent document (if you embed
+sub-documents). 
 
-For example, if you have an ``Event`` class, that you extend in Java (e.g.
-``MachineEvent`` or ``NetworkEvent``), using the discriminator identifies
+For example, if you have an ``Event`` class that you extend in Java (e.g.
+``MachineEvent`` or ``NetworkEvent``), using a discriminator identifies
 which class the ``PojoCodecProvider`` should use to serialize/deserialize the
 document. 
 
+For more information, see our :ref:`POJO Customization guide
+<pojo-discriminators>`. 
+
 Can I control serialization of ``LocalDate``?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~