Editor: Fix how the Site Editor is linked to

- Add 'Edit site' to the top admin bar.
- Link to the Template and Template Part CPTs.
- Add deep link to the Global Styles UI.

Follows [52069].
See #54337.


git-svn-id: https://develop.svn.wordpress.org/trunk@52158 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/menu.php

@@ -212,6 +212,12 @@ if ( wp_is_block_template_theme() ) {
 		'edit_theme_options',
 		'site-editor.php',
 	);
+
+	$submenu['themes.php'][7] = array(
+		__( 'Styles' ),
+		'edit_theme_options',
+		'site-editor.php?styles=open',
+	);
 }
 
 // Hide Customize link on block themes unless a plugin or theme is using