bulkwritecommandexception.xml Fix typo (#4701)

Author: mmalferov

reference/mongodb/mongodb/driver/exception/bulkwritecommandexception.xml

@@ -104,7 +104,7 @@
       <para>
        A <classname>MongoDB\Driver\BulkWriteCommandResult</classname> reporting
        the result of any successful operations that were performed before the
-       error was encountered. This value may not &null; if it cannot be
+       error was encountered. This value may be &null; if it cannot be
        determined that at least one write was successfully performed (and
        acknowledged).
       </para>