Editable public edge between graph endpoints.
@type t() :: %Docket.Graph.Edge{ description: String.t() | nil, from: String.t() | [String.t()] | nil, guard: Docket.Guard.t() | nil, id: String.t() | nil, label: String.t() | nil, metadata: map(), source_handle: String.t() | nil, target_handle: String.t() | nil, to: String.t() | nil }