REST API: add revisions endpoint for global styles.

Adds an endpoint that returns revisions to the global styles custom post.

Props ramonopoly, peterwilsoncc, spacedmonkey, mukesh27, timothyblynjacobs.
Fixes #58524.

Built from https://develop.svn.wordpress.org/trunk@56082


git-svn-id: http://core.svn.wordpress.org/trunk@55594 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api.php

@@ -317,6 +317,10 @@ function create_initial_rest_routes() {
 	$controller = new WP_REST_Block_Types_Controller();
 	$controller->register_routes();
 
+	// Global Styles revisions.
+	$controller = new WP_REST_Global_Styles_Revisions_Controller();
+	$controller->register_routes();
+
 	// Global Styles.
 	$controller = new WP_REST_Global_Styles_Controller();
 	$controller->register_routes();