optional route param does't work

[Trezedo]

Environment

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- Operating System: `Windows_NT`
- Node Version:     `v16.13.0`
- Nuxt Version:     `3.0.0-rc.3`
- Package Manager:  `yarn@1.22.18`
- Builder:          `vite`
- User Config:      `buildModules`, `typescript`, `css`, `autoImports`, `vite`
- Runtime Modules:  `-`
- Build Modules:    `@pinia/nuxt@0.1.9`
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Reproduction

minimal reproduction: stackblitz.com

Describe the bug

Optional route params do not work, though it was reported #13846 .

Both the path /test/ and /u-author/tag/ return with 404 not found. While ~/pages/test/[[slug]].vue is supposed to enable optional params as the document says.

In file .nuxt/dist/server/server.mjs, the generated route is /test/:slug instead of the expected /test/:slug?:

Additional context

No response

Logs

No response