Fix

Author: mcmorisi

source/upgrade/v3.txt

@@ -110,7 +110,7 @@ Version 3.0 Breaking Changes
 
 - Previous versions of the {+driver-short+} supported two GUID representation modes.
   In version 3.0, ``GuidRepresentationMode.V3`` is the only supported mode. This change
-  has the following effects on the driver:
+  has the following effect on the driver:
 
   - The ``BsonBinaryData(Guid)`` constructor has been removed. To construct a ``BsonBinaryData``
     object from a GUID, use the ``BsonBinaryData.Create(Guid, GuidRepresentation)`` constructor.