wip: rename/clarify later departures

lib/config/v2/departures/layout.ex

@@ -11,18 +11,22 @@ defmodule ScreensConfig.V2.Departures.Layout do
   If `max` is not set, the section may grow to fill all available space. If `base` is not set, it
   defaults to the value of `max`.
 
-  If `overflow` is set, departures that don't fit in the main list (up to `max`) overflow into a
-  paging "Later Departures" component.
+  If `include_later` is set, the section includes a paging "Later Departures" component, which
+  shows departures that would have otherwise been dropped due to space constraints (plus as many
+  further-out departures as it has space for). The other fields do not "count" departures shown
+  here; in other words, a section with `%{base: 4, max: 6, include_later: true}` is treated as
+  desiring 4-6 departures that are visible at all times, and if more are available, however many
+  will fit in "Later Departures" in addition to that.
   """
 
   @type t :: %__MODULE__{
           base: pos_integer() | nil,
+          include_later: boolean(),
           max: pos_integer() | nil,
-          min: pos_integer(),
-          overflow: boolean()
+          min: pos_integer()
         }
 
-  defstruct base: nil, max: nil, min: 1, overflow: false
+  defstruct base: nil, include_later: false, max: nil, min: 1
 
   use ScreensConfig.Struct, with_default: true