adds specs for spending proposal code

app/views/spending_proposals/show.html.erb

@@ -16,7 +16,7 @@
       </div>
 
       <br>
-      <p>
+      <p id="spending_proposal_code">
         <%= t("spending_proposals.show.code") %>
         <strong><%= @spending_proposal.id %></strong>
       </p>

spec/features/spending_proposals_spec.rb

@@ -181,6 +181,9 @@ feature 'Spending proposals' do
     expect(page).to have_content(spending_proposal.author.name)
     expect(page).to have_content(spending_proposal.association_name)
     expect(page).to have_content(spending_proposal.geozone.name)
+    within("#spending_proposal_code") do
+      expect(page).to have_content(spending_proposal.id)
+    end
   end
 
   context "Destroy" do