Avoid ref when using format! in compiler

Clean up a few minor refs in `format!` macro, as it has a performance cost. Apparently the compiler is unable to inline `format!("{}", &variable)`, and does a run-time double-reference instead (format macro already does one level referencing).  Inlining format args prevents accidental `&` misuse.

compiler/rustc_codegen_ssa/src/mono_item.rs

@@ -130,7 +130,7 @@ impl<'a, 'tcx: 'a> MonoItemExt<'a, 'tcx> for MonoItem<'tcx> {
 
         let symbol_name = self.symbol_name(cx.tcx()).name;
 
-        debug!("symbol {}", &symbol_name);
+        debug!("symbol {symbol_name}");
 
         match *self {
             MonoItem::Static(def_id) => {