[Feature request] - Override of the getChoiceIndex function should be available via options object on initialization #464

I use vue-i18n via another lib nuxt-i18n so I doesn't have direct access to the library to override getChoiceIndex method in a clean way as it described in the documentation and my personal opinion is that it looks dirty to to this at all. Instead, what I like is to be able to do override this method via default vue-i18n config object. The syntax is pretty simple:

new VueI18n({
  locale: 'pl', // set locale
  getChoiceIndex(choice, choicesLength) {
     // Custom pluralization code goes here
  }
})

so when using nuxt-i18n module I can simply do:

modules: [ ['nuxt-i18n', {
locales: [...], 
vueI18n: {
   getChoiceIndex(choice, choicesLength) {
     // Custom pluralization code goes here
  }
}
}]]

I think such approach is much more cleaner to use!