Update data-accessor-functions-string-xquery.md

Author: Court72

docs/xquery/data-accessor-functions-string-xquery.md

@@ -1,6 +1,6 @@
 ---
 title: "string Function (XQuery) | Microsoft Docs"
-description: Learn about the XQuery function string() that returns the value of it's argument represented as a string.
+description: Learn about the XQuery function string() that returns the value of its argument represented as a string.
 ms.custom: ""
 ms.date: "03/09/2017"
 ms.prod: sql