docs: fix broken link for out-of-box plugin references

[adam0x01]

Summary

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Docs
• Build-related changes
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If changing the UI of default theme, please provide the before/after screenshot:

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• No

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The PR fulfills these requirements:

• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)

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• Related documents have been updated
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To avoid wasting your time, it's best to open a feature request issue first and wait for approval before working on it.

Other information:

[adam0x01]

Fix the 404 links on page https://vuepress.vuejs.org/plugin/#plugins-that-come-with-the-default-theme

[billyyyyy3320]

Thanks