Handle plural (and 0) on orders selection component

app/views/spree/admin/orders/index.html.haml

@@ -24,8 +24,12 @@
     - if Spree::Config[:enable_invoices?]
       .ofn-drop-down-with-prepend
         .ofn-drop-down-prepend{"ng-class": "selected_orders.length == 0 ? 'disabled' : ''"}
-          {{ selected_orders.length }}
-          =t('.selected')
+          %span{"ng-show" => "selected_orders.length == 0"}
+            = t('.selected.zero')
+          %span{"ng-show" => "selected_orders.length == 1"}
+            = t('.selected.one')
+          %span{"ng-show" => "selected_orders.length > 1"}
+            = t('.selected.many', count: "{{ selected_orders.length }}")
         .ofn-drop-down{"ng-class": "selected_orders.length == 0 ? 'disabled' : ''"}
           %span{ :class => 'icon-reorder' }
             ="#{t('admin.actions')}".html_safe

config/locales/en.yml

@@ -3774,7 +3774,10 @@ See the %{link} to find out more about %{sitename}'s features and to start using
           results_found: "%{number} Results found."
           viewing: "Viewing %{start} to %{end}."
           print_invoices: "Print Invoices"
-          selected: selected
+          selected:
+            zero: "No order selected"
+            one: "1 order selected"
+            many: "%{count} orders selected"
         sortable_header:
           payment_state: "Payment State"
           shipment_state: "Shipment State"