Update the path of tls_key_generate.sh script (#4756)

docs/en/setup/backend/grpc-ssl.md

@@ -11,7 +11,7 @@ You can follow below steps to enable this feature
 It seems like step one is to generate certificates and key files for encrypting communication. I thought this would be
 fairly straightforward using `openssl` from the command line.
 
-Use this [script](../../../../../tools/TLS/tls_key_generate.sh) if you are not familiar with how to generate key files.
+Use this [script](../../../../tools/TLS/tls_key_generate.sh) if you are not familiar with how to generate key files.
 
 We need below files:
  - `server.pem` a private RSA key to sign and authenticate the public key.