private void insertBefore(Node item) {
			item.prev = prev;
			item.next = this;

			if (this.prev == null) {
				head = item;
			}
			else {
				this.prev.next = item;
			}
			this.prev = item;
		}
Insert a node as a predecessor to this node in the linked list

NOTE: Called only after the node is inserted into the tree
Ghidra/Framework/Generic/src/main/java/ghidra/generic/util/datastruct/TreeValueSortedMap.java