Auto merge of #84457 - jyn514:cleanup-crate, r=GuillaumeGomez

rustdoc: Remove most fields from ExternalCrate

Once https://github.com/rust-lang/rust/issues/84304 is fixed, I can get rid of ExternCrate altogether in favor of CrateNum, but in the meantime, this shrinks ExternalCrate quite a lot.

This might hurt compile-times; if it does, I can add `primitive` and `keyword` queries. I expect this to improve compilemem.

Helps with https://github.com/rust-lang/rust/issues/76382.

r? GuillaumeGomez

diff --cc src/librustdoc/clean/types.rs
Simple merge