Add comment to prompt changing of pepper

synapse/config/password.py

@@ -31,6 +31,7 @@ class PasswordConfig(Config):
         password_config:
            enabled: true
            # Uncomment for extra security for your passwords.
+           # Change to a secret random string.
            # DO NOT CHANGE THIS AFTER INITIAL SETUP!
            #pepper: "HR32t0xZcQnzn3O0ZkEVuetdFvH1W6TeEPw6JjH0Cl+qflVOseGyFJlJR7ACLnywjN9"
         """
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