vale fixes

Author: Chris Cho

source/whats-new.txt

@@ -358,7 +358,7 @@ New features of the 1.7 Go driver release include:
   multi-document transactions for certain read operations.
 
 - Improved ``WriteException`` and ``BulkWriteException`` error messages for
-  schema validation via the ``WriteError.Details`` field.
+  schema validation reported by the ``WriteError.Details`` field.
 
 
 .. _version-1.6:
@@ -432,7 +432,7 @@ What's New in 1.3
 New features of the 1.3 Go driver release include:
 
 - ``mgocompat`` package that exports a BSON registry compatible with
-  ``globalsign/mgo/bson``, which can be used via the
+  ``globalsign/mgo/bson``, which can be used by calling the
   ``ClientOptions.SetRegistry`` method.
 
 - ``RegisterTypeEncoder`` and ``RegisterHookEncoder`` methods, which
@@ -471,7 +471,7 @@ New features of the 1.1 Go driver release include:
   performance.
 
 - Connection Monitoring and Pooling specifications to monitor various connection
-  and connection pool events with improved utilization.
+  and connection pool events with improved efficiency.
 
 
 .. _version-1.0: