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](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_errors/src/emitter.rs

@@ -337,9 +337,7 @@ pub trait Emitter: Translate {
                     && last_name != name
                 {
                     let descr = macro_kind.descr();
-                    format!(
-                        " which comes from the expansion of the {descr} `{last_name}`",
-                    )
+                    format!(" which comes from the expansion of the {descr} `{last_name}`",)
                 } else {
                     "".to_string()
                 };
@@ -1935,7 +1933,9 @@ impl EmitterWriter {
                     is_multiline,
                 )
             }
-            if let DisplaySuggestion::Add = show_code_change && is_item_attribute {
+            if let DisplaySuggestion::Add = show_code_change
+                && is_item_attribute
+            {
                 // The suggestion adds an entire line of code, ending on a newline, so we'll also
                 // print the *following* line, to provide context of what we're advising people to
                 // do. Otherwise you would only see contextless code that can be confused for

compiler/rustc_errors/src/lib.rs

@@ -1673,7 +1673,11 @@ impl HandlerInner {
                 let _ = write!(
                     &mut out,
                     "delayed span bug: {}\n{}\n",
-                    bug.inner.styled_message().iter().filter_map(|(msg, _)| msg.as_str()).collect::<String>(),
+                    bug.inner
+                        .styled_message()
+                        .iter()
+                        .filter_map(|(msg, _)| msg.as_str())
+                        .collect::<String>(),
                     &bug.note
                 );
             }

compiler/rustc_errors/src/tests.rs

@@ -151,12 +151,14 @@ fn misformed_fluent() {
             primary: box TranslateError::One { kind: TranslateErrorKind::PrimaryBundleMissing, .. },
             fallback: box TranslateError::One { kind: TranslateErrorKind::Fluent { errs }, .. },
         } = &err
-            && let [FluentError::ResolverError(ResolverError::Reference(
-                ReferenceKind::Message { id, .. }
-                    | ReferenceKind::Variable { id, .. },
-            ))] = &**errs
+            && let [
+                FluentError::ResolverError(ResolverError::Reference(
+                    ReferenceKind::Message { id, .. } | ReferenceKind::Variable { id, .. },
+                )),
+            ] = &**errs
             && id == "name"
-        {} else {
+        {
+        } else {
             panic!("{err:#?}")
         };
         assert_eq!(
@@ -176,12 +178,14 @@ fn misformed_fluent() {
             primary: box TranslateError::One { kind: TranslateErrorKind::PrimaryBundleMissing, .. },
             fallback: box TranslateError::One { kind: TranslateErrorKind::Fluent { errs }, .. },
         } = &err
-            && let [FluentError::ResolverError(ResolverError::Reference(
-                ReferenceKind::Message { id, .. }
-                    | ReferenceKind::Variable { id, .. },
-            ))] = &**errs
+            && let [
+                FluentError::ResolverError(ResolverError::Reference(
+                    ReferenceKind::Message { id, .. } | ReferenceKind::Variable { id, .. },
+                )),
+            ] = &**errs
             && id == "oops"
-        {} else {
+        {
+        } else {
             panic!("{err:#?}")
         };
         assert_eq!(