upd linked-blocks

Author: olton

examples/linked-block.html

@@ -28,7 +28,7 @@
         <button onclick="createBlocksCTop()">C Top</button>
         <button onclick="createBlocksCBottom()">C Bottom</button>
         <button onclick="createBlocksCSide()">C Side</button>
-        <button onclick="Metro.getPlugin('.linked-block.active-block', 'linked-block').destroy()">Destroy</button>
+        <button onclick="Metro.getPlugin('.linked-block.active-block', 'linked-block')?.destroy()">Destroy</button>
     </div>
     <div class="app-bar-item-static no-hover ml-auto">
         <input type="checkbox" data-role="theme-switcher"/>