Add link to ETCD/JDBC Registry Guideline

[pegasas]

Purpose of the pull request

Add link to ETCD/JDBC Registry Guideline fix https://github.com/apache/dolphinscheduler/issues/15591

Brief change log

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This pull request is code cleanup without any test coverage.

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This pull request is already covered by existing tests, such as (please describe tests).

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This change added tests and can be verified as follows:

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If your pull request contain incompatible change, you should also add it to docs/docs/en/guide/upgrede/incompatible.md