AG-16871 improve readme

Squashed commit of the following:

commit 6162f41b80c1370ad7bb68f321eec429f62176c8
Author: Slava Leleka <[email protected]>
Date:   Fri Oct 7 15:28:04 2022 +0300

    fix description

commit 453949cfe02f42d57cfc8fb74e72689d31bd870f
Author: Slava Leleka <[email protected]>
Date:   Fri Oct 7 14:34:21 2022 +0300

    add few badges to readme

commit bb8a9168e47e006afec74803f126c32bd575c3c4
Author: Slava Leleka <[email protected]>
Date:   Fri Oct 7 14:29:30 2022 +0300

    improve lib description

README.md

@@ -1,6 +1,8 @@
-# <a id="homepage"> ExtendedCss
+# <a id="homepage"></a> ExtendedCss ![npm](https://img.shields.io/npm/v/@adguard/extended-css) [![install size](https://packagephobia.com/badge?p=@adguard/extended-css)](https://packagephobia.com/result?p=@adguard/extended-css) ![GitHub](https://img.shields.io/github/license/AdGuardTeam/ExtendedCss)
 
-AdGuard's ExtendedCss library for applying CSS styles with extended selection properties.
+AdGuard's TypeScript library for non-standard element selecting and applying CSS styles with extended properties.
+
+The idea of extended capabilities is an opportunity to match DOM elements with selectors based on their own representation (style, text content, etc.) or relations with other elements. There is also an opportunity to apply styles with non-standard CSS properties.
 
 * [Extended capabilities](#extended-capabilities)
   * [Limitations](#extended-css-limitations)

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@adguard/extended-css",
   "version": "2.0.0",
-  "description": "AdGuard's JavaScript library for applying CSS styles with extended selection properties.",
+  "description": "AdGuard's TypeScript library for non-standard element selecting and applying CSS styles with extended properties.",
   "main": "dist/extended-css.umd.js",
   "module": "dist/extended-css.esm.js",
   "typings": "dist/types",