encryption at rest: update docs

[en-jin19]

What is changed, added or deleted? (Required)

• Updated the document "encryption-at-rest.md".
• The changes of PR 7140 have been included in this PR, so I closed #7140.

Which TiDB version(s) do your changes apply to? (Required)

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For details, see tips for choosing the affected versions (in Chinese).

• master (the latest development version)
• v5.2 (TiDB 5.2 versions)
• v5.1 (TiDB 5.1 versions)
• v5.0 (TiDB 5.0 versions)
• v4.0 (TiDB 4.0 versions)
• v3.1 (TiDB 3.1 versions)
• v3.0 (TiDB 3.0 versions)
• v2.1 (TiDB 2.1 versions)

What is the related PR or file link(s)?

• This PR is translated from:

1. encryption-at-rest: Update docs#6152
2. Suggest Log Redaction when using TDE docs#6147

• Other reference link(s):

Do your changes match any of the following descriptions?

• Delete files
• Change aliases
• Need modification after applied to another branch
• Might cause conflicts after applied to another branch

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• TomShawn

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[TomShawn]

Good translation! Well done.
These are only minor comments~

[TomShawn]

/remove-status LGT1
/status LGT2

[TomShawn]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: eefb210

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #7282.