I see now why it did not work for you. I implemented pagination for post_snippets shortode while you were looking for pagination that works for category_posts shortcode. Will make the code changes and get back to you on this. Thanks
I created a new page template for you on your site. That looks to be solution that you wanted than have pagination for shortcodes. Pagination for shortcodes can be really confusing specially if you have other content in your site. If you have more than one shortcode with pagination enabled for each, it becomes even more confusing to the user. I am guessing that you need a news page which lists all the news items. I created a page template for you and a sample page as well. Pls have a look and hope it meets your need. Uploaded a new file named template-news.php to your site. Pls preserve this for your use.
Here is how you can modify the original news page (change template and add custom field to indicate your layout) –