Rollup merge of #105537 - kadiwa4:remove_some_imports, r=fee1-dead

compiler: remove unnecessary imports and qualified paths

Some of these imports were necessary before Edition 2021, others were already in the prelude.

I hope it's fine that this PR is so spread-out across files :/

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -31,7 +31,6 @@ use rustc_trait_selection::traits::{
 };
 
 use std::cell::LazyCell;
-use std::convert::TryInto;
 use std::iter;
 use std::ops::{ControlFlow, Deref};