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

packages/ckeditor5-admonition/docs/api/block-quote.md

@@ -0,0 +1,36 @@
+---
+category: api-reference
+---
+
+# CKEditor 5 block quote feature
+
+[![npm version](https://badge.fury.io/js/%40ckeditor%2Fckeditor5-block-quote.svg)](https://www.npmjs.com/package/@ckeditor/ckeditor5-block-quote)
+
+This package implements block quote support for CKEditor 5.
+
+## Demo
+
+Check out the {@link features/block-quote#demo demo in the block quote feature guide}.
+
+## Documentation
+
+See the {@link features/block-quote block quote feature guide} and the {@link module:block-quote/blockquote~BlockQuote} plugin documentation.
+
+## Installation
+
+This package is part of our open-source aggregate package.
+
+```bash
+npm install ckeditor5
+```
+
+## Contribute
+
+The source code of this package is available on GitHub in [https://github.com/ckeditor/ckeditor5/tree/master/packages/ckeditor5-block-quote](https://github.com/ckeditor/ckeditor5/tree/master/packages/ckeditor5-block-quote).
+
+## External links
+
+* [`@ckeditor/ckeditor5-block-quote` on npm](https://www.npmjs.com/package/@ckeditor/ckeditor5-block-quote)
+* [`ckeditor/ckeditor5-block-quote` on GitHub](https://github.com/ckeditor/ckeditor5/tree/master/packages/ckeditor5-block-quote)
+* [Issue tracker](https://github.com/ckeditor/ckeditor5/issues)
+* [Changelog](https://github.com/ckeditor/ckeditor5/blob/master/CHANGELOG.md)