Update selectors for latest GitLab version

gitlab.user.js

@@ -18,9 +18,9 @@
 
 new TogglButtonGM('.issue-details', function (elem) {
   var description, projectIds = [],
-    id = elem.querySelector('.page-title .issue-id'),
-    titleElem = elem.querySelector('.issue-box .title, .issue-title'),
-    projectElem = document.querySelector('.title');
+    id = elem.querySelector('.detail-page-header .identifier'),
+    titleElem = elem.querySelector('.issue-details h2.title'),
+    projectElem = elem.querySelector('h1.title span');
 
   description = titleElem.textContent.trim();
   if (id !== null) {