Fix Devise deprecation warning

DEPRECATION WARNING: [Devise] `DeviseHelper.devise_error_messages!`
is deprecated and it will be removed in the next major version.
To customize the errors styles please run `rails g devise:views` and
modify the `devise/shared/error_messages` partial.

We will render the resource errors instead fo calling the deprecated method.

app/views/users/registrations/delete_form.html.erb

@@ -5,7 +5,7 @@
 <%= form_for(resource, as: resource_name,
              url: users_registrations_path,
              html: { method: :delete }) do |f| %>
-  <%= devise_error_messages! %>
+  <%= render "shared/errors", resource: resource %>
 
   <div data-alert class="callout alert">
     <%= t("devise_views.users.registrations.delete_form.info") %>

app/views/users/registrations/edit.html.erb

@@ -3,7 +3,7 @@
 <h2><%= t("devise_views.users.registrations.edit.edit") %></h2>
 
 <%= form_for(resource, as: resource_name, url: registration_path(resource_name), html: { method: :put }) do |f| %>
-  <%= devise_error_messages! %>
+  <%= render "shared/errors", resource: resource %>
   <div class="row">
     <div class="small-12 column">
       <%= f.label :email, t("devise_views.users.registrations.edit.email_label") %>