Add a way to add description to virtual modules

[sapphi-red]

Clear and concise description of the problem

I think it would be helpful for users if there's a description for each virtual modules. For example:

• rolldown/runtime.js: rolldown's utilty functions that are used in the bundle
• vite/modulepreload-polyfill.js: Vite's modulepreload polyfill. See https://vite.dev/config/build-options#build-modulepreload
• ./src/App.vue?vue&type=script&setup=true&lang.ts: <script> block of ./src/App.vue

Suggested solution

Recommend plugins to add meta.devtools.description values in load hook.

const p = {
  name: 'foo',
  load(id) {
    return { code: content, meta: { devtools: { description: 'Vite's modulepreload polyfill. See https://vite.dev/config/build-options#build-modulepreload' } } }
  }
}

and make devtools will read that information.

Alternative

Add the metadata on plugin object:

const p = {
  name: 'foo',
  meta: {
    devtools: {
      virtualmodulesDescription: {
        'vite/modulepreload-polyfill.js': 'Vite's modulepreload polyfill. See https://vite.dev/config/build-options#build-modulepreload',
      }
    }
  }
}

This does not allow setting the description for dynamic virtual modules.

Additional context

No response

Validations

• Follow our Code of Conduct
• Read the Contributing Guide.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.

[antfu]

I would be up to have the load return approach. but as such data is collected by rolldown, and the description is actually not specific to devtools, I wonder if it should be directly description instead of meta.devtools.description