t() :: %Ash.Resource.Relationships.ManyToMany{
  cardinality: :many,
  destination: Ash.resource(),
  destination_field: atom(),
  destination_field_on_join_table: atom(),
  join_attributes: [atom()],
  join_relationship: atom(),
  name: atom(),
  source: Ash.resource(),
  source_field: atom(),
  source_field_on_join_table: atom(),
  through: Ash.resource(),
  type: :many_to_many,
  writable?: boolean()
}