docs: change library description phrase

Author: gnapse

README.md

@@ -5,7 +5,7 @@
 <img height="80" width="80" alt="owl" src="https://raw.githubusercontent.com/gnapse/jest-dom/master/other/owl.png" />
 </a>
 
-<p>Custom jest matchers to test the dom structure</p>
+<p>Custom jest matchers to test the state of the DOM</p>
 </div>
 
 <hr />

package.json

@@ -1,7 +1,7 @@
 {
   "name": "jest-dom",
   "version": "0.0.0-semantically-released",
-  "description": "Custom jest matchers to test the dom structure",
+  "description": "Custom jest matchers to test the state of the DOM",
   "main": "dist/index.js",
   "engines": {
     "node": "> 4",