Width selector (typically for layout/grid systems).
type WidthField<T extends FieldValue = FieldValue> = LabeledValue<T>;
type ColumnWidth = WidthField<25 | 33 | 50 | 66 | 75 | 100>;
// Result: {
// value: 25 | 33 | 50 | 66 | 75 | 100,
// label: string,
// key: 25 | 33 | 50 | 66 | 75 | 100
// }