Rollup merge of #119600 - aDotInTheVoid:comment-fix, r=compiler-errors

Remove outdated references to librustc_middle

The relevant comment is now in 791a53f380/compiler/rustc_middle/src/tests.rs (L3-L13)

compiler/rustc_data_structures/src/lib.rs

@@ -148,7 +148,7 @@ pub fn make_display(f: impl Fn(&mut fmt::Formatter<'_>) -> fmt::Result) -> impl
     Printer { f }
 }
 
-// See comments in src/librustc_middle/lib.rs
+// See comments in compiler/rustc_middle/src/tests.rs
 #[doc(hidden)]
 pub fn __noop_fix_for_27438() {}