Fix some pdf errors

app/models/pdf_documents/customer_report.rb

@@ -77,9 +77,9 @@ module PdfDocuments
           move_down 5
           check.links.group_by(&:link_category).each do |cat, links|
             rich_text(%Q(
-              <b>#{cat.name}</b>
+              <span>#{cat.name}</span>
               <ul>
-                #{links.map{ "<li><link href='#{_1.url}'>#{_1.text}</link></li>" }.join() }
+                #{links.map{ "<li><a href='#{_1.url}'>#{_1.text}</a></li>" }.join() }
               </ul>
             ))
           end
@@ -157,8 +157,10 @@ module PdfDocuments
       end
       heading4("Protokollnummer")
       text(success_criterion.number)
+      safe_display(success_criterion.check.external_url) do
         heading4("WCAG")
-      text("<link href='#{success_criterion.check.external_url}'>#{success_criterion.check.external_number}</link>", inline_format: true)
+        text("<link href='#{_1}'>#{success_criterion.check.external_number || _1}</link>", inline_format: true)
+      end
       move_down(10)
     end
   end