refactor: add quick reply placeholder

templates/partials/topic/quickreply.tpl

@@ -12,7 +12,7 @@
 		<input type="hidden" name="tid" value="{tid}" />
 		<input type="hidden" name="_csrf" value="{config.csrf_token}" />
 		<div class="quickreply-message">
-			<textarea name="content" component="topic/quickreply/text" class="form-control" rows="5"></textarea>
+			<textarea name="content" component="topic/quickreply/text" class="form-control" rows="5" placeholder="[[modules:composer.textarea.placeholder]]"></textarea>
 			<div class="imagedrop"><div>[[topic:composer.drag_and_drop_images]]</div></div>
 		</div>
 		<button type="submit" component="topic/quickreply/button" class="btn btn-primary pull-right">[[topic:post-quick-reply]]</button>