fix(nuxt2): support nuxt2

[poyoho]

fix: #1832

autoimport unocss will generate the code

import 'uno.css'
export default defineNuxtPlugin(() => {})

but defineNuxtPlugin is not autoimport in pure nuxt2

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[zyyv]

I test this example, but it doesn't work properly. So did this commit really solve the problem?

[poyoho]

@zyyv what the error do you meet?

[zyyv]

@zyyv what the error do you meet?

[zyyv]

Can you try to run it?

[poyoho]

I can run it. Can you provide the mini repo thanks 😀

[zyyv]

I'm just run https://github.com/unocss/unocss/tree/main/examples/nuxt2-webpack.
let me check it carefully again.