1.104.2 LinkedList: adding

add: aLink

Add aLink at the end of the list; return aLink.

addFirst: aLink

Add aLink at the head of the list; return aLink.

addLast: aLink

Add aLink at then end of the list; return aLink.

remove: aLink ifAbsent: aBlock

Remove aLink from the list and return it, or invoke aBlock if it’s not found in the list.

removeFirst

Remove the first element from the list and return it, or error if the list is empty.

removeLast

Remove the final element from the list and return it, or error if the list is empty.