Create some sort of sub types to force the presence of important keys

[adan-ea]

Hi there, I'm currently implementing this library into my project and I really enjoy using it.
But there is still something I feel is missing
My project is a discord bot so I usually have the same structure in the i18n file i.e.:

{
  "embed": {
    "fields": {
      "message": {
        "name": "",
        "value": ""
      },
      "votes": {
        "name": "",
        "value": ""
      },
      "origin": {
        "name": "",
        "value": ""
      }
    }
  }
}

And so, it would be a very nice addition if I could somehow create a type for this part of the object when the key is embed that would look like this:

interface EmbedField {
    name: string;
    value: string;
}

interface Embed {
    title: string,
    description: string,
    fields: {
        [key: string]: EmbedField;
    };
}