Auto merge of #125105 - nnethercote:rustc_resolve-cleanups, r=estebank

`rustc_resolve` cleanups

Some improvements I found while looking through this code.

r? `@estebank`

compiler/rustc_resolve/src/effective_visibilities.rs

@@ -11,6 +11,7 @@ use rustc_middle::middle::privacy::Level;
 use rustc_middle::middle::privacy::{EffectiveVisibilities, EffectiveVisibility};
 use rustc_middle::ty::Visibility;
 use std::mem;
+use tracing::info;
 
 #[derive(Clone, Copy)]
 enum ParentId<'a> {