DOCSP-27808 Adds warning on partition fields with dots (#2755) (#2770)

* DOCSP-27808 Adds warning on partition fields with  dots

* Fixes per Dave

Author: kennethdyer

source/core/document.txt

@@ -179,6 +179,10 @@ For example, given the following field in a document:
 - To specify the ``number`` in the ``phone`` document in the
   ``contact`` field, use the dot notation ``"contact.phone.number"``.
 
+.. warning::
+
+   Partition fields cannot use field names that contain a dot (``.``). 
+
 For examples querying embedded documents, see:
 
 - :doc:`/tutorial/query-embedded-documents`