Martin von Zweigbergk f877610792 merge: add Merge::num_sides()
An alternative name for it would be `arity()`, but `num_sides()`
probably more clearly says that it's not about the number of removes
or the total number of terms.
2023-08-25 08:54:49 -07:00
..
2023-08-25 08:54:49 -07:00