Enhanced Authentication Documentation Suggestions

> 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.*

Start with the SCRAM authentication page linked in the issue and review its explanation of MQTT 5.0 support. Update the documentation to explain how users with MQTT 3.1.1 devices should handle this limitation, then verify that the guidance is clear and consistent with the page.

Written by the indexing model from the issue text.