Support Self for intra links paths

[GuillaumeGomez]

Fixes #49583.

r? @QuietMisdreavus

[QuietMisdreavus]

I don't see how this will work if there are more than one item with self links in them, or if the item with self links in them isn't the very last thing in the crate. The place where you're setting the item ID is well before it's used, since rustdoc doesn't bother cleaning the attributes until after the code in visit_ast.rs is completely finished.

A better solution would be to replace the impl Clean<Attributes> for [ast::Attributes] with a function that takes the DocContext, the attributes, and the ID you need, to make sure it's always available. It's going to be a tedious fix (since we save the attributes on nearly everything) but it's also foolproof and doesn't rely on making sure you've properly swapped the ID in and out.

[pietroalbini]

Ping from triage! What's the status on this?

[GuillaumeGomez]

It needs big changes.

[pietroalbini]

Weekly ping from triage @GuillaumeGomez! Just making sure this is not forgotten.

[TimNN]

Ping from triage, @GuillaumeGomez: We haven't heard from you in two weeks, so we are closing this for now to keep the PR queue clean. Feel free to reopen in the future!