Remove unused property on the example

Author: abdonrd

README.md

@@ -118,7 +118,7 @@ into the element. This is the only method that must be implemented by subclasses
 ```html
   <script src="node_modules/@webcomponents/webcomponentsjs/webcomponents-bundle.js"></script>
   <script type="module">
-    import {LitElement, html, property} from '@polymer/lit-element';
+    import {LitElement, html} from '@polymer/lit-element';
 
     class MyElement extends LitElement {
 
@@ -279,4 +279,4 @@ Chrome, Safari, Opera, Firefox, Edge. In addition, Internet Explorer 11 is also
 platform properties like (`id` or `name`) may not have default values set in the element constructor.
 On these browsers native properties appear on instances and therefore their default value
 will overwrite any element default (e.g. if the element sets this.id = 'id' in the constructor,
-the 'id' will become '' since this is the native platform default).
+the 'id' will become '' since this is the native platform default).