C26914: Escaping '@' character to avoid SxS issue (#6141)

Author: v-maudel

docs/framework/wcf/feature-details/generating-a-wcf-client-from-service-metadata.md

@@ -14,7 +14,7 @@ This topic describes how to use the various switches in Svcutil.exe to generate
 
 -   DISCO request (using the [DiscoveryClientProtocol](http://go.microsoft.com/fwlink/?LinkId=94777) from ASP.NET Web services) to the supplied address.  
 
- Svcutil.exe generates the client based on the Web Services Description Language (WSDL) or policy file received from the service. The user principal name (UPN) is generated by concatenating the user name with "@" and then adding a fully-qualified domain name (FQDN). However, for users who registered on Active Directory, this format is not valid and the UPN that the tool generates causes a failure in the Kerberos authentication with the following error message: **The logon attempt failed.** To resolve this problem, manually fix the client file that the tool generated.  
+ Svcutil.exe generates the client based on the Web Services Description Language (WSDL) or policy file received from the service. The user principal name (UPN) is generated by concatenating the user name with "\@" and then adding a fully-qualified domain name (FQDN). However, for users who registered on Active Directory, this format is not valid and the UPN that the tool generates causes a failure in the Kerberos authentication with the following error message: **The logon attempt failed.** To resolve this problem, manually fix the client file that the tool generated.  
 
 ```  
 svcutil.exe [/t:code]  <metadataDocumentPath>* | <url>* | <epr>