Fix new issue header text

Without the leading `=`, this is just interpreted as literal text, so it
won't be translated.

app/views/projects/issues/new.html.haml

@@ -2,8 +2,7 @@
 - breadcrumb_title _("New")
 - page_title _("New Issue")
 
-%h3.page-title
-  _("New Issue")
+%h3.page-title= _("New Issue")
 %hr
 
 = render "form"