Add support for passing TSdoc for the generated types

[tijmenb]

Description 📖

This allows you to pass a doc string for the attribute:

class VideoSerializer < BaseSerializer
  type :string, optional: true, doc: "URL to the video on YouTube"
  def youtube_url
    video.youtube_url
  end
end

Which translates into a TSDoc-compliant comment:

export default interface Video {
  /**
  * URL to the video on YouTube
  */
  youtubeUrl?: string
}

Background 📜

We're using types_from_serializers to generate the types and docs for parts of our API. This will allow us to document the attributes that we expose.

The Fix 🔨

Add a doc attribute to the types.

Screenshots 📷