docs: update the TiKV store status description

[JmPotato]

Signed-off-by: JmPotato ghzpotato@gmail.com

What is changed, added or deleted? (Required)

Refine the TiKV store status description.

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

Tips for choosing the affected version(s):

By default, CHOOSE MASTER ONLY so your changes will be applied to the next TiDB major or minor releases. If your PR involves a product feature behavior change or a compatibility change, CHOOSE THE AFFECTED RELEASE BRANCH(ES) AND MASTER.

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

• master (the latest development version)
• v6.0 (TiDB 6.0 versions)
• v5.4 (TiDB 5.4 versions)
• v5.3 (TiDB 5.3 versions)
• 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)?

• Other reference link(s): Update TiKV store status information docs#6949

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• shichun-0415

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[JmPotato]

/cc @en-jin19 @shichun-0415

[shichun-0415]

Great job. Thanks.

[shichun-0415]

/merge

[ti-chi-bot]

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

Commit hash: f400373

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #8727.

[ti-chi-bot]

In response to a cherrypick label: new pull request could not be created: failed to create pull request against pingcap/docs-cn#release-5.2 from head ti-chi-bot:cherry-pick-8723-to-release-5.2: status code 422 not one of [201], body: {"message":"Validation Failed","errors":[{"resource":"PullRequest","code":"custom","message":"A pull request already exists for ti-chi-bot:cherry-pick-8723-to-release-5.2."}],"documentation_url":"https://docs.github.com/rest/reference/pulls#create-a-pull-request"}

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #8728.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #8729.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #8730.

[ti-chi-bot]

In response to a cherrypick label: new pull request created: #8731.