Use tracing macro syntax instead of format()

Author: Stypox

compiler/rustc_const_eval/src/interpret/eval_context.rs

@@ -325,8 +325,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let _span = enter_trace_span!(
             M,
             "instantiate_from_frame_and_normalize_erasing_regions",
-            "{}",
-            frame.instance
+            %frame.instance
         );
         frame
             .instance

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -1418,7 +1418,9 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
         let _span = enter_trace_span!(
             M,
             "validate_operand",
-            "recursive={recursive}, reset_provenance_and_padding={reset_provenance_and_padding}, val={val:?}"
+            recursive,
+            reset_provenance_and_padding,
+            ?val,
         );
 
         // Note that we *could* actually be in CTFE here with `-Zextra-const-ub-checks`, but it's