Add back the check for hierarchical post types, instead of just relying on page-attributes

[dkotter]

Description of the Change

In #103, we changed our sortable check to only rely on if a post type supports page-attributes. This broke sorting for sites that use post types that are hierarchical but don't have that attribute set. While it may better align with how core is set up to only look at page-attributes, it seems best to revert that change so we're not breaking functionality on sites that rely on the old behavior.

This isn't a complete revert of the changes introduced in #103 but does bring back the missing functionality.

How to test the Change

1. Create a post type that has page-attributes set
2. Add content to this post type
3. Ensure you can sort this content and it reflects properly on the front-end
4. Create a post type that doesn't have page-attributes set but is set as hierarchical
5. Run through the same test steps and ensure things work

Changelog Entry

Changed - Allow hierarchical post types that don't have page-attributes set to be sorted.

Credits

Props @dkotter

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[peterwilsoncc]

LGTM and tests well.

Is it worth changing the How can I exclude certain custom post types? section of the readme to:

---

How can I modify sortable post types?

Post types can be included or excluded by using the simple_page_ordering_is_sortable filter.

For example, to exclude the excluded_post_type custom post type, add the following snippet in the theme function file or custom plugin:

add_filter( 'simple_page_ordering_is_sortable', function( $sortable, $post_type ) {
	if ( 'excluded_post_type' === $post_type ) {
		return false;
	}
	return $sortable;
}, 10, 2 );

To include the include_post_type custom post type, add the following snippet in the theme function file or custom plugin:

add_filter( 'simple_page_ordering_is_sortable', function( $sortable, $post_type ) {
	if ( 'include_post_type' === $post_type ) {
		return true;
	}
	return $sortable;
}, 10, 2 );