Update ns-System.Data.SqlClient.xml (dotnet#10757)

Author: gewarren

xml/ns-System.Data.SqlClient.xml

@@ -4,11 +4,15 @@
     <remarks>
       <format type="text/markdown"><![CDATA[  
   
-## Remarks  
- The .NET Data Provider for SQL Server describes a collection of classes used to access a SQL Server database in the managed space. Using the <xref:System.Data.SqlClient.SqlDataAdapter>, you can fill a memory-resident <xref:System.Data.DataSet> that you can use to query and update the database.  
+## Remarks
+
+> [!NOTE]
+> The <xref:System.Data.SqlClient> APIs are deprecated. For new development, use the <xref:Microsoft.Data.SqlClient> APIs.
+
+The .NET Data Provider for SQL Server describes a collection of classes used to access a SQL Server database in the managed space. Using the <xref:System.Data.SqlClient.SqlDataAdapter>, you can fill a memory-resident <xref:System.Data.DataSet> that you can use to query and update the database.  
   
 > [!NOTE]
->  For conceptual information about using this namespace when programming with .NET, see [SQL Server and ADO.NET](/dotnet/framework/data/adonet/sql/).  
+> For conceptual information about using this namespace when programming with .NET, see [SQL Server and ADO.NET](/dotnet/framework/data/adonet/sql/).  
   
  ]]></format>
     </remarks>