Function append_list

fn append_list(
    constraints: &mut IndexSlice<NllMemberConstraintIndex, NllMemberConstraint<'_>>,
    target_list: NllMemberConstraintIndex,
    source_list: NllMemberConstraintIndex,
)

Given a linked list starting at source_list and another linked list starting at target_list, modify target_list so that it is followed by source_list.

Before:

target_list: A -> B -> C -> (None)
source_list: D -> E -> F -> (None)

After:

target_list: A -> B -> C -> D -> E -> F -> (None)