update elements and fix some bugs

lib/paper_badge.dart

 // DO NOT EDIT: auto-generated with `pub run custom_element_apigen:update`
 
 /// Dart API for the polymer element `paper_badge`.
 @HtmlImport('paper_badge_nodart.html')
 library polymer_elements.lib.src.paper_badge.paper_badge;
 
 import 'dart:html';
 import 'dart:js' show JsArray, JsObject;
 import 'package:web_components/web_components.dart';
 import 'package:polymer_interop/polymer_interop.dart';
 import 'iron_resizable_behavior.dart';
 import 'iron_flex_layout.dart';
 import 'default_theme.dart';
 
 /// `<paper-badge>` is a circular text badge that is displayed on the top right
 /// corner of an element, representing a status or a notification. It will badge
 /// the anchor element specified in the `for` attribute, or, if that doesn't exist,
 /// centered to the parent node containing it.
 ///
 /// Example:
 ///
 ///     <div style="display:inline-block">
 ///       <span>Inbox</span>
 ///       <paper-badge label="3"></paper-badge>
 ///     </div>
 ///
 ///     <div>
-///       <paper-button id="btn">Status</button>
-///       <paper-badge for="btn" label="♥︎">b/paper-badge>
+///       <paper-button id="btn">Status</paper-button>
+///       <paper-badge for="btn" label="♥︎"></paper-badge>
 ///     </div>
 ///
 /// ### Styling
 ///
 /// The following custom properties and mixins are available for styling:
 ///
 /// Custom property | Description | Default
 /// ----------------|-------------|----------
 /// `--paper-badge-background` | The background color of the badge | `--accent-color`
 /// `--paper-badge-opacity` | The opacity of the badge | `1.0`
@@ skipping 27 matching lines @@
   /// automatically when the badge is attached or an `iron-resize` event is
   /// fired (for exmaple if the window has resized, or your target is a
   /// custom element that implements IronResizableBehavior).
   ///
   /// You should call this in all other cases when the achor's position
   /// might have changed (for example, if it's visibility has changed, or
   /// you've manually done a page re-layout).
   updatePosition() =>
       jsElement.callMethod('updatePosition', []);
 }