Fixed style issues

app/views/shared/issuable/_sidebar.html.haml

@@ -128,7 +128,7 @@
           .title.hide-collapsed
             Notifications
           - subscribtion_status = subscribed ? 'subscribed' : 'unsubscribed'
-          %button.btn.btn-block.btn-gray.js-subscribe-button.issuable-subscribe-button.hide-collapsed{:type => 'button'}
+          %button.btn.btn-block.btn-gray.js-subscribe-button.issuable-subscribe-button.hide-collapsed{ type: "button" }
             %span= subscribed ? 'Unsubscribe' : 'Subscribe'
           .subscription-status.hide-collapsed{data: {status: subscribtion_status}}
             .unsubscribed{class: ( 'hidden' if subscribed )}