Rollup merge of #129648 - nnethercote:unreachable_pub-2, r=Urgau

More `unreachable_pub`

Add `unreachable_pub` checking to some more compiler crates. A follow-up to #126013.

r? ``@Urgau``

compiler/rustc_interface/src/lib.rs

@@ -2,6 +2,7 @@
 #![feature(decl_macro)]
 #![feature(let_chains)]
 #![feature(try_blocks)]
+#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod callbacks;