All Submissions:

• Have you followed the WooCommerce Contributing guideline?
• Does your code follow the WordPress' coding standards?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

This PR re-works the WC_Shipping_Zone_Data_Store::read() method in the following ways:

1. Remove a confusing conditional (if ( 0 !== $zone->get_id() || '0' !== $zone->get_id() ) { ... })
2. Return early if we're dealing with Zone 0, eliminating additional conditional steps
3. Add documentation for the "woocommerce_shipping_zone_loaded" action hook

How to test the changes in this Pull Request:

1. Create a new shipping zone within WooCommerce (if one does not exist)
2. Attempt to read the shipping zone from the database (WP Admin is a good place to do so)

The shipping zone should load as it did before.

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully run tests with your changes locally?

Changelog entry

Dev- Clean up the WC_Shipping_Zone_Data_Store::read() method, documenting the woocommerce_shipping_zone_loaded hook.