ConstAutoFill.Presets is the registry and says what each preset does; this says what it is named, so
a fill menu, a Series dialog, or a caller's own picker all read the same word for date.weekdays.
Keyed by preset id rather than by filler, because a filler appears under several presets —
linear and linear.trend are the same filler and are not the same entry.
Where those entries SIT — their order, and which of them a given surface even lists — is that surface's own business and lives with it.
What a surface CALLS each fill type.