Merge branch '15413-firefox-line-numbers' into 'master'

Remove float from blame link icon

Closes #15413   
<img src="/uploads/af6aea9102e1b42e5e92783ce818863c/Screen_Shot_2016-04-21_at_1.57.56_PM.png" width="200px">



See merge request !3861

app/assets/stylesheets/framework/files.scss

@@ -131,6 +131,11 @@
       td.line-numbers {
         float: none;
         border-left: 1px solid #ddd;
+
+        i {
+          float: none;
+          margin-right: 0;
+        }
       }
       td.lines {
         padding: 0;