Display datetime when hovering the date in chat message, see #1020

app/widgets/Chat/chat.js

@@ -967,6 +967,7 @@ var Chat = {
             msg = document.createElement('div');
             span = document.createElement('span');
             span.className = 'info';
+
             p = document.createElement('p');
             reaction = reaction.cloneNode(true);
 
@@ -1073,6 +1074,10 @@ var Chat = {
             msg.appendChild(resourceSpan);
         }
 
+        if (data.published) {
+            span.title = data.published;
+        }
+
         if (data.card) {
             bubble.querySelector('div.bubble').classList.add('file');
             msg.appendChild(Chat.getCardHtml(data.card));