Rollup merge of #138084 - nnethercote:workspace-lints, r=jieyouxu

Use workspace lints for crates in `compiler/`

This is nicer and hopefully less error prone than specifying lints via bootstrap.

r? ``@jieyouxu``

compiler/rustc_incremental/src/lib.rs

@@ -7,7 +7,6 @@
 #![doc(rust_logo)]
 #![feature(file_buffered)]
 #![feature(rustdoc_internals)]
-#![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
 mod assert_dep_graph;