[Feature Request] Let vuedoc better comment nested data

Summary Lets say in the data variable we have the following code:

data(){
  return {
    /** The Information required to manage the form */
    form: {
      /** The name that is currently selected */
      name: undefined,
      /** The title that is currently selected */
      title: undefined,
      ...
    }
  }
}

The result of node_modules/.bin/vuedoc.md filename.vue is:

- `form`

  The Information required to manage the form

**initial value:** `[object Object]`

It would be better if the output could describe the nested data values such as:

- `form`

  The Information required to manage the form

**initial value:** `[object Object]`
  
  - name
      The name that is currently selected
  - title
  etc. 

Of course this is just an example and the comments in the actual project will be more descriptive, but i believe this is a useful feature to have.