docs(hooks): update delete_blog/deleted_blog xrefs

Update 2 cross-references for deprecated delete_blog
and deleted_blog hooks from `ms-blogs.php` to
`ms-site.php` where the hooks now live.

Related to https://core.trac.wordpress.org/ticket/64224

Author: apermo

src/wp-admin/includes/ms.php

@@ -97,7 +97,7 @@ function wpmu_delete_blog( $blog_id, $drop = false ) {
 	if ( $drop ) {
 		wp_delete_site( $blog_id );
 	} else {
-		/** This action is documented in wp-includes/ms-blogs.php */
+		/** This action is documented in wp-includes/ms-site.php */
 		do_action_deprecated( 'delete_blog', array( $blog_id, false ), '5.1.0' );
 
 		$users = get_users(
@@ -116,7 +116,7 @@ function wpmu_delete_blog( $blog_id, $drop = false ) {
 
 		update_blog_status( $blog_id, 'deleted', 1 );
 
-		/** This action is documented in wp-includes/ms-blogs.php */
+		/** This action is documented in wp-includes/ms-site.php */
 		do_action_deprecated( 'deleted_blog', array( $blog_id, false ), '5.1.0' );
 	}