syntax: rename author_user in author

css/notification.css

@@ -148,7 +148,7 @@ sib-display-value{
   flex-grow: 1;
   padding-right: 0.8rem;
 }
-.sib-notifications__items [name="author_user.username"]{
+.sib-notifications__items [name="author.username"]{
   font-weight: bold;
   font-size: 1rem;
 }
@@ -161,7 +161,7 @@ sib-display-value{
   color: #AAA;
   font-size: 75%;
 }
-.sib-notifications__items [name="author_user.avatar"]{
+.sib-notifications__items [name="author.avatar"]{
   display: block;
   width: 30px;
   height: 30px;

sib-notifications.js

@@ -123,10 +123,10 @@ class SIBNotifications extends SIBTemplateElement {
             class="sib-notifications__items"
             data-src="${sourceUrl}"
             widget-unread="read-badge"
-            set-wrapper="author_user.username, type, date"
-            set-content="author_user.avatar, wrapper"
+            set-wrapper="author.username, type, date"
+            set-content="author.avatar, wrapper"
             data-fields="unread, content"
-            widget-author_user.avatar="sib-display-img"
+            widget-author.avatar="sib-display-img"
             paginate-by="10"></sib-display>
           </div>
         </details>