chore(admonitions): start off with a fresh copy of blockquote plugin

packages/ckeditor5-admonition/docs/_snippets/features/nested-block-quote.js

@@ -0,0 +1,15 @@
+/**
+ * @license Copyright (c) 2003-2024, CKSource Holding sp. z o.o. All rights reserved.
+ * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
+ */
+
+/* globals ClassicEditor, window, document, console */
+
+ClassicEditor
+	.create( document.querySelector( '#snippet-nested-block-quote' ) )
+	.then( editor => {
+		window.editor2 = editor;
+	} )
+	.catch( err => {
+		console.error( err.stack );
+	} );