Update file path

Author: ninallam

articles/load-testing/how-to-use-multiple-certificates.md

@@ -95,6 +95,6 @@ Review all configurations to ensure correctness. Click **Create Test** to finali
 
 ## Related content
 
-* [Use a Managed Identity in Azure Load Testing](./how-to-use-a-managed-identity)
+* [Use a Managed Identity in Azure Load Testing](./how-to-use-a-managed-identity.md)
 
-* [Use Secrets and Certificates in Azure Load Testing](./how-to-use-secrets-and-certificates)
+* [Use Secrets and Certificates in Azure Load Testing](./how-to-use-secrets-and-certificates.md)