Add an option to extract for each emitted entry the token { start, end }

In order to be able to generate an automatic outline symbols for an SFC component, it would be great to have an option to extract for each emitted entry, the token { start, end }.

So the Entry interface could become:

interface Entry {
  readonly kind: string,
  visibility: 'public' | 'protected' | 'private',
  description: string,
  keywords: Keyword[],
  start: number,
  end: number
}