Add title for autoscroll status indicator for a11y

app/views/projects/builds/show.html.haml

@@ -64,7 +64,7 @@
               %span.scroll-step-label Scroll to bottom
           - if @build.active?
             .autoscroll-container
-              %span.status-message#autoscroll-status{:data => {:state => 'enabled'}}
+              %span.status-message#autoscroll-status{:data => {:state => 'enabled'}, :title => 'Autoscroll active'}
                 %i.fa.fa-toggle-on
                 %label Autoscroll active
         #up-build-trace