Filters the number of items per page to show for a specific ‘per_page’ type.

The dynamic portion of the hook name, $post_type, refers to the post type.

Possible hook names include:

• edit_post_per_page
• edit_page_per_page
• edit_attachment_per_page

$posts_per_page = apply_filters( "edit_{$post_type}_per_page", $posts_per_page );