episode: also use microphone as symbol in search results

panikweb_templates/templates/episodes/search_result.html

 <a href="{% url 'episode-view' emission_slug=result.emission_slug slug=result.slug %}">
-	<span class="icon-comment  " ></span>
+	<span class="icon-microphone"></span>
 	<strong>{{ result.title }}</strong>
 	<br />
 	<span class="smooth">{{ result.emission_title }}</span>