Update source/mapping-rules/fields/data-type-conversion-guide.txt

Co-authored-by: Ashley Brown <[email protected]>

Author: ianf-mongodb

source/mapping-rules/fields/data-type-conversion-guide.txt

@@ -21,7 +21,7 @@ Behavior
   Your field's null handling strategy does not affect this 
   behavior.
 
-- Your sync job continues with errors unless it reaches threshold
+- Your sync job continues with errors unless it reaches the threshold
   that you defined when you created the sync job.
 
 - .. include:: /includes/fact-calculated-fields-type.rst