Merge pull request dotnet#2954 from iss0/patch-1

Fixed typo in syntax example.

Author: Ron Petrusha

Diff for: docs/framework/configure-apps/file-schema/wcf/certificate-for-identity.md

@@ -26,7 +26,7 @@ Specifies an X.509 certificate used to validate a server to a client.
 ## Syntax  
 
 ```xml  
-<certificate encodedValue = "Sring" />  
+<certificate encodedValue = "String" />  
 ```  
 
 ## Attributes and Elements