Auto merge of #115694 - clarfonthey:std-hash-private, r=dtolnay

Add `std::hash::{DefaultHasher, RandomState}` exports (needs FCP)

This implements rust-lang/libs-team#267 to move the libstd hasher types to `std::hash` where they belong, instead of `std::collections::hash_map`.

<details><summary>The below no longer applies, but is kept for clarity.</summary>
This is a small refactor for #27242, which moves the definitions of `RandomState` and `DefaultHasher` into `std::hash`, but in a way that won't be noticed in the public API.

I've opened rust-lang/libs-team#267 as a formal ACP to move these directly into the root of `std::hash`, but for now, they're at least separated out from the collections code in a way that will make moving that around easier.

I decided to simply copy the rustdoc for `std::hash` from `core::hash` since I think it would be ideal for the two to diverge longer-term, especially if the ACP is accepted. However, I would be willing to factor them out into a common markdown document if that's preferred.
</details>

1 files changed, 1 insertions, 2 deletions

diff --git a/compiler/rustc_middle/src/ty/error.rs b/compiler/rustc_middle/src/ty/error.rs
index 738bb5e8b19..b26f98769c1 100644
--- a/compiler/rustc_middle/src/ty/error.rs
+++ b/compiler/rustc_middle/src/ty/error.rs
@@ -7,8 +7,7 @@ use rustc_hir::def_id::DefId;
 use rustc_span::symbol::Symbol;
 use rustc_target::spec::abi;
 use std::borrow::Cow;
-use std::collections::hash_map::DefaultHasher;
-use std::hash::{Hash, Hasher};
+use std::hash::{DefaultHasher, Hash, Hasher};
 use std::path::PathBuf;
 
 #[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable)]