Idle feeds: show tooltip with last update date

https://github.com/marienfressinaud/FreshRSS/issues/544

app/views/stats/idle.phtml

@@ -1,17 +1,17 @@
 <?php $this->partial('aside_stats'); ?>
 
 <div class="post content">
-	<a href="<?php echo _url ('index', 'index'); ?>"><?php echo _t ('back_to_rss_feeds'); ?></a>
+	<a href="<?php echo _url('index', 'index'); ?>"><?php echo _t('back_to_rss_feeds'); ?></a>
 
-	<h1><?php echo _t ('stats_idle'); ?></h1>
+	<h1><?php echo _t('stats_idle'); ?></h1>
 
-	<?php foreach ($this->idleFeeds as $period => $feeds){ ?>
+	<?php foreach ($this->idleFeeds as $period => $feeds) { ?>
 		<div class="stat">
-			<h2><?php echo _t ($period); ?></h2>
+			<h2><?php echo _t($period); ?></h2>
 
 			<ul>
-				<?php foreach ($feeds as $feed){ ?>
-					<li><a href="<?php echo _url('configure', 'feed', 'id', $feed['id']); ?>"><?php echo $feed['name']; ?></a></li>
+				<?php foreach ($feeds as $feed) { ?>
+					<li><a href="<?php echo _url('configure', 'feed', 'id', $feed['id']); ?>" title="<?php echo date('Y-m-d', $feed['last_date']); ?>"><?php echo $feed['name']; ?></a></li>
 				<?php } ?>
 			</ul>
 		</div>