Bug 1388509 - Fix tab-icon-overlay alignment on pinned tabs. r=daleharvey

MozReview-Commit-ID: 5RnSb9Yd8sI

--HG--
extra : rebase_source : aa9876f3ffa181b74508bb79c259a646e0f0ddb8

browser/themes/shared/tabs.inc.css

@@ -131,8 +131,8 @@
   width: 16px;
   height: 16px;
   margin-top: -8px;
-  margin-inline-start: -15px;
-  margin-inline-end: -1px;
+  margin-inline-start: -6px;
+  margin-inline-end: -10px;
   position: relative;
 }