feat:linked list add new method

traverse linked list is easy but uninteresting. You must add new variable and use while.So why not add a method to return a iterator.Then we can use for of to traverse. eg:

getIterator() {
    const _this = this
    return {
      *[Symbol.iterator]() {
        let currentNode = _this.head
        if (!currentNode) yield node
        while (currentNode) {
          yield currentNode.value
          currentNode = currentNode.next
        }
      }
    }
  }

use

const iter = linkedList.getIterator()
for(const item of iter){
 console.log(item)
} 

The issue names no implementation file or test. Locate the linked-list implementation and its existing traversal-related tests, then review how iteration is currently exposed. Done means the linked list supports the proposed iterator and for-of traversal, with behavior verified for populated and empty lists.