Rollup merge of #84345 - ehuss:remove-core-core-comment, r=Mark-Simulacrum

Remove comment about doc hack.

I neglected to remove this comment in #83955.

Author: Dylan-DPC

src/bootstrap/doc.rs

@@ -461,15 +461,6 @@ impl Step for Std {
         // create correct links between crates because rustdoc depends on the
         // existence of the output directories to know if it should be a local
         // or remote link.
-        //
-        // There's also a mild hack here where we build the first crate in this
-        // list, core, twice. This is currently necessary to make sure that
-        // cargo's cached rustc/rustdoc versions are up to date which means
-        // cargo won't delete the out_dir we create for the stampfile.
-        // Essentially any crate could go into the first slot here as it's
-        // output directory will be deleted by us (as cargo will purge the stamp
-        // file during the first slot's run), and core is relatively fast to
-        // build so works OK to fill this 'dummy' slot.
         let krates = ["core", "alloc", "std", "proc_macro", "test"];
         for krate in &krates {
             run_cargo_rustdoc_for(krate);