int $num, WP_Post $post )
Filters the number of revisions to save for the given post by its post type.
Overrides both the value of WP_POST_REVISIONS and the ‘wp_revisions_to_keep’ filter.
The dynamic portion of the hook name,
$post->post_type, refers to the post type slug.
Possible hook names include:
(int) Number of revisions to store.
(WP_Post) Post object.