merged two sorted linked lists.

[shalupatidar22]

This pull request introduces a function that merges two sorted singly linked lists into one sorted linked list. The key changes include:

Node Structure: Defines the structure for linked list nodes with data and next pointers.
Linked List Operations:
create() and create2(): Initialize two linked lists from two separate arrays.
merge(): Merges two pre-sorted linked lists into a new sorted linked list.
display(): Recursively displays the contents of the linked list.