FIX: invalid html in notification emails when template has been customized

lib/email/sender.rb

@@ -51,8 +51,6 @@ module Email
         end
       end
 
-      @message.parts[0].body = @message.parts[0].body.to_s.gsub(/\[\/?email-indent\]/, '')
-
       # Fix relative (ie upload) HTML links in markdown which do not work well in plain text emails.
       # These are the links we add when a user uploads a file or image.
       # Ideally we would parse general markdown into plain text, but that is almost an intractable problem.

lib/email/styles.rb

@@ -186,10 +186,7 @@ module Email
     def to_html
       strip_classes_and_ids
       replace_relative_urls
-      @fragment.to_html.tap do |result|
-        result.gsub!(/\[email-indent\]/, "<div style='margin-left: 15px'>")
-        result.gsub!(/\[\/email-indent\]/, "</div>")
-      end
+      @fragment.to_html
     end
 
     def strip_avatars_and_emojis