docs: add explicit createError import

[mtskf]

❓ Type of change

• [x ] 📖 Documentation (updates to the documentation or readme)

📚 Description

createError should be imported from h3 otherwise Nuxt will throw an error:

[nuxt] [request error] createError is not defined

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

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[danielroe]

What version of Nuxt are you on?

[mtskf]

@danielroe 3.0.0-rc.6

[danielroe]

Try edge releases. It will be auto imported in the next release.

[pi0]

Thanks for the PR @mtskf. As @danielroe pointed out, the auto import feature for createError is merged with #4539 but still in the edge channel. I've moved your solution to a temporary banner until next release.