Update toc wording for consistency

[lilin90]

What is changed, added or deleted? (Required)

Make the wording in TOC.md consistent with the document title for 读写延迟增加, and with wording in the English version https://docs.pingcap.com/tidb/dev/troubleshoot-cpu-issues

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[ti-chi-bot]

[LGTM Timeline notifier]

Timeline:

• 2024-05-09 10:42:40.584409083 +0000 UTC m=+1131514.341544655: ☑️ agreed by hfxsd.

[lilin90]

/approve

[ti-chi-bot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: lilin90

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[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.5: #17305.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.6: #17306.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.1: #17307.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-6.5: #17308.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-7.1: #17309.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.4: #17310.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-8.0: #17311.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.1: #17312.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.2: #17313.

[ti-chi-bot]

In response to a cherrypick label: new pull request created to branch release-5.3: #17314.