Enhanced Authentication Documentation Suggestions

[tigercl]

https://www.emqx.io/docs/zh/latest/access-control/authn/scram.html

SCRAM authentication only supports connections using MQTT v5.0.

Since enhanced authentication only supports MQTT 5.0 devices, but users might also have MQTT 3.1.1 devices that need to connect, it would be best if the documentation could explain how to handle this situation.

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This issue was automatically translated from Chinese.