Insert new posts at given position

[justsanjit]

There was a use case where I needed to insert new posts at a specific position within the order. Upon researching, I found a relevant discussion on the WordPress forum. The current implementation did not support this feature, so I decided to implement it based on the forum discussion.

This PR introduces a new filter reorder_post_within_categories_new_post_position. This filter is an enhancement of the existing reorder_post_within_categories_new_post_first filter, providing additional functionality to support positive and negative integer values for positioning new posts.

add_filter('reorder_post_within_categories_new_post_position', 'rank_new_posts', 10, 3);
function rank_new_posts($is_first, $post, $term_id){
    return 3;
}

• If the filter returns a positive value, the new post will be inserted at the specified position.
• If the filter returns a negative value, the new post will be inserted counting from the end of the array.
• If the filter returns a null value, the ranking will default to the behavior of the reorder_post_within_categories_new_post_first filter.