C-CRATE-DOC should explain, not link

[ralfbiedert]

While practically all other guidelines are very pleasant to read and extremely useful, C-CRATE-DOC is an empty placeholder that leads down a confusing rabbit hole.

If you click it you end up on an RFC thread, where you have to scroll down a few posts to find a link to a "Rendered" RFC 1687 document, which in turn is an amendment to RFC 1574, from all of which you have to piece together what C-CRATE-DOC might be about.

Instead, C-CRATE-DOC should just be written like every other guideline, without linking to another resource.

[KodrAus]

It would be great to add some concrete guidance here. It looks like we never got back around to that postponed RFC but its content should make a good starting point.