adds back link to admin's spending proposal show

app/views/admin/spending_proposals/show.html.erb

@@ -1,3 +1,4 @@
+<%= link_to t("admin.spending_proposals.show.back"), :back, class: 'back' %>
 <h2><%= t("admin.spending_proposals.show.heading") %> <%= @spending_proposal.id %></h2>
 <h1><%= @spending_proposal.title %></h1>
 

config/locales/admin.en.yml

@@ -164,6 +164,7 @@ en:
           other: "%{count} valuators assigned"
         no_valuators_assigned: No valuators assigned
       show:
+        back: Back
         heading: Investment project
         info: Author info
         association_name: Asociación

config/locales/admin.es.yml

@@ -164,6 +164,7 @@ es:
           other: "%{count} evaluadores asignados"
         no_valuators_assigned: Sin evaluador
       show:
+        back: Volver
         heading: Propuesta de inversión
         info: Datos de envío
         association_name: Asociación