minor #541 Add trash icon for 'Delete post' button (bocharsky-bw)

This PR was merged into the master branch.

Discussion
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Add trash icon for 'Delete post' button

Before:
<img width="275" alt="screen shot 2017-04-21 at 00 38 27" src="https://cloud.githubusercontent.com/assets/3317635/25253758/ea99a98e-262a-11e7-91a9-7754e356144b.png">

After:
<img width="283" alt="screen shot 2017-04-21 at 00 37 59" src="https://cloud.githubusercontent.com/assets/3317635/25253766/f4092e90-262a-11e7-8f34-e0fcce5c1821.png">

Commits
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d7c0fdb Add trash icon for 'Delete post' button

Author: javiereguiluz

app/Resources/views/admin/blog/_delete_form.html.twig

@@ -1,5 +1,8 @@
 {{ include('blog/_delete_post_confirmation.html.twig') }}
 <form action="{{ url('admin_post_delete', {id: post.id}) }}" method="post" data-confirmation="true" id="delete-form">
     <input type="hidden" name="token" value="{{ csrf_token('delete') }}" />
-    <input type="submit" value="{{ 'action.delete_post'|trans }}" class="btn btn-lg btn-block btn-danger" />
+    <button type="submit" class="btn btn-lg btn-block btn-danger">
+        <i class="fa fa-trash" aria-hidden="true"></i>
+        {{ 'action.delete_post'|trans }}
+    </button>
 </form>