Auto merge of #116688 - compiler-errors:rustfmt-up, r=WaffleLapkin,Nilstrieb

Format all the let-chains in compiler crates

Since rust-lang/rustfmt#5910 has landed, soon we will have support for formatting let-chains (as soon as rustfmt syncs and beta gets bumped).

This PR applies the changes [from master rustfmt to rust-lang/rust eagerly](https://rust-lang.zulipchat.com/#narrow/stream/122651-general/topic/out.20formatting.20of.20prs/near/374997516), so that the next beta bump does not have to deal with a 200+ file diff and can remain concerned with other things like `cfg(bootstrap)` -- #113637 was a pain to land, for example, because of let-else.

I will also add this commit to the ignore list after it has landed.

The commands that were run -- I'm not great at bash-foo, but this applies rustfmt to every compiler crate, and then reverts the two crates that should probably be formatted out-of-tree.
```
~/rustfmt $ ls -1d ~/rust/compiler/* | xargs -I@ cargo run --bin rustfmt -- `@/src/lib.rs` --config-path ~/rust --edition=2021 # format all of the compiler crates
~/rust $ git checkout HEAD -- compiler/rustc_codegen_{gcc,cranelift} # revert changes to cg-gcc and cg-clif
```

cc `@rust-lang/rustfmt`
r? `@WaffleLapkin` or `@Nilstrieb` who said they may be able to review this purely mechanical PR :>

cc `@Mark-Simulacrum` and `@petrochenkov,` who had some thoughts on the order of operations with big formatting changes in https://github.com/rust-lang/rust/pull/95262#issue-1178993801. I think the situation has changed since then, given that let-chains support exists on master rustfmt now, and I'm fairly confident that this formatting PR should land even if *bootstrap* rustfmt doesn't yet format let-chains in order to lessen the burden of the next beta bump.

compiler/rustc_lint/src/async_fn_in_trait.rs

@@ -117,9 +117,12 @@ impl<'tcx> LateLintPass<'tcx> for AsyncFnInTrait {
                 def.owner_id.def_id,
                 " + Send",
             );
-            cx.tcx.emit_spanned_lint(ASYNC_FN_IN_TRAIT, item.hir_id(), async_span, AsyncFnInTraitDiag {
-                sugg
-            });
+            cx.tcx.emit_spanned_lint(
+                ASYNC_FN_IN_TRAIT,
+                item.hir_id(),
+                async_span,
+                AsyncFnInTraitDiag { sugg },
+            );
         }
     }
 }