Fix columns in vote view headers

app/modules/vote/templates/vote/view.j2

@@ -1,10 +1,10 @@
 {% extends "layout/backend.j2" %}
 {% block content %}
 <div class="row">
-	<div class="col-lg-10">
+	<div class="col-12 col-md">
 		<h1>Vote: {{ ballot.name }}</h1>
 	</div>
-	<div class="col-lg-2 mb-3 text-right">
+	<div class="col-auto mb-3 text-right">
 		<a href="{{ url_for('vote.add_question', ballot_id=ballot.id) }}"><button class="btn btn-secondary btn-sm">Add question</button></a>
 	</div>
 </div>