@type t() :: %ExDoc.ExtraNode{
  doc: ExDoc.DocAST.t() | nil,
  group: atom() | nil,
  id: String.t(),
  search_data: [map()] | nil,
  source_doc: String.t(),
  source_path: String.t(),
  source_url: String.t(),
  title: String.t(),
  title_doc: ExDoc.DocAST.t() | String.t(),
  type: atom()
}