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Issue

Hi,

Using the example from README

plugins
│   ├── hooked-plugin
│   │   ├── autohooks.js // req.hookOne = 'yes' # CJS syntax
│   │   ├── routes.js
│   │   └── children
│   │       ├── old-routes.js
│   │       ├── new-routes.js
│   │       └── grandchildren
│   │           ├── autohooks.mjs // req.hookTwo = 'yes' # ESM syntax
│   │           └── routes.mjs
│   └── standard-plugin
│       └── routes.js

Say new-routes.js has a route with fastify.patch('/entity', ...

That is available at http://.../hooked-plugin/children/entity , as by default dirNameRoutePrefix is set. So far so good.

In new-routes.js, I've set

export const autoPrefix = '/batch'

I would have expected the route to be now at http://.../hooked-plugin/children/batch/entity but instead is at
http://.../hooked-plugin/batch/entity
If this is intended behavior, would you please mention in README for autoPrefix that it overwrites, not appends, to folder structure path?
This isn't consistent with When setting both options.prefix and plugin.autoPrefix they will be concatenated., but at least it's documented.

Thanks!