docs(nx-plugin): update some missed old paths

[forivall]

Current Behavior

Some installation instructions are using incorrect old package names for @nrwl/nx-plugin

Expected Behavior

Installation instructions should use package names for @nx/plugin

Related Issue(s)

Fixes #

[vercel]

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Name	Status	Preview	Updated (UTC)
nx-dev	✅ Ready (Inspect)	Visit Preview	Oct 27, 2023 8:45pm

[nx-cloud]

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✅ Successfully ran 6 targets

• nx affected --target=e2e --base=e4d1ef3cf37e69fd8431d82b6f4de213c9c41c85 --head=75b82e3364328ca73ae7d3020b3b5ea5936adf8b --parallel=1
• nx affected --targets=lint,test,build --base=e4d1ef3cf37e69fd8431d82b6f4de213c9c41c85 --head=75b82e3364328ca73ae7d3020b3b5ea5936adf8b --parallel=3
• nx run-many -t check-imports check-commit check-lock-files check-codeowners documentation --parallel=1 --no-dte
• nx-cloud record -- nx format:check --base=e4d1ef3cf37e69fd8431d82b6f4de213c9c41c85 --head=75b82e3364328ca73ae7d3020b3b5ea5936adf8b
• nx documentation --no-dte
• nx affected -t e2e-macos --parallel=1 --base=e4d1ef3cf37e69fd8431d82b6f4de213c9c41c85 --head=75b82e3364328ca73ae7d3020b3b5ea5936adf8b

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Sent with 💌 from NxCloud.

[FrozenPandaz]

Thank you for your contribution! LGTM 🎉

[github-actions]

This pull request has already been merged/closed. If you experience issues related to these changes, please open a new issue referencing this pull request.