Show warnings in edit forms.

Make all edit forms show warnings in addition to errors. Also render
warnings and errors using DText.

Currently this only affects artists and wiki pages because they're the
only pages that have warnings.

app/helpers/application_helper.rb

@@ -252,7 +252,11 @@ module ApplicationHelper
 
     simple_form_for(model, **options) do |form|
       if model.try(:errors).try(:any?)
-        concat tag.div(model.errors.full_messages.join("; "), class: "notice notice-error notice-small")
+        concat tag.div(format_text(model.errors.full_messages.join("; ")), class: "notice notice-error notice-small prose")
+      end
+
+      if model.try(:warnings).try(:any?)
+        concat tag.div(format_text(model.warnings.full_messages.join("; ")), class: "notice notice-info notice-small prose")
       end
 
       block.call(form)