Site editor: update custom post types with _edit_link

[ramonjd]

What?

Resolves: #48065

Hello!

This PR backports the following functionality from Core:

• adds an _edit_link property to wp_global_styles, wp_template, and wp_template-part custom post type schemata via filter
• uses the _edit_link value to create an edit link via the get_edit_post_link hook

Why?

A revisions link was added to view revisions for templates and template parts.

This link takes the user to the WordPress revision.php screen. Here there are two links that should link back to the editor.

But since the custom post types schemata did not contain an _edit_link property, the links were broken.

wp_global_styles was covered for the sake of completion.

This was recently fixed in Core and already has test coverage:

• Links to the editor don't work for template and template parts revisions in the revisions screen #48065
• https://core.trac.wordpress.org/ticket/57709

But 6.3 won't be out until later in the year. August?

How?

register_post_type_args and get_edit_post_link filters

Testing Instructions

1. Spin up this branch and head over to the site editor.
2. Make a few (more than 1) changes to a template and also to a template part
3. In the right-hand-side inspector, select the "Template" menu item and click on the "Revisions" button
4. You should be taken to revision.php. Now make sure that the two links, e.g., Compare Revisions of “header” and ← Go to editor take you back to the site editor with the right template in edit mode.

[draganescu]

Thank you :) I forgot the links are filterable and I was worried we can't backport the edits to ghe get edit link function. 👏 the power of hooks once again saves the day. Great work @ramonjd 🚢