Feature request: crawling of supplements

[cxcorp]

I noticed when checking out the data, that articles tagged as supplement don't get crawled. These are e.g. experiment logs, interviews, etc. linked to from an item or tale, but which don't really have a hub or index page that links to all of them, other than the tag.

An example: the scp-507 page links to document-507-3b, which is missing from the dataset.

I'm not sure if this is working as intended or not, but I figured I'd mention it.