Rollup merge of #118199 - compiler-errors:qpath, r=lcnr

Remove `HirId` from `QPath::LangItem`

Remove `HirId` from `QPath::LangItem`, since there was only *one* use-case (`ObligationCauseCode::AwaitableExpr`), which we can instead recover by walking the HIR tree.

compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs

@@ -1087,7 +1087,7 @@ impl<'a, 'tcx> FindInferSourceVisitor<'a, 'tcx> {
 
                 Box::new(segment.into_iter())
             }
-            hir::QPath::LangItem(_, _, _) => Box::new(iter::empty()),
+            hir::QPath::LangItem(_, _) => Box::new(iter::empty()),
         }
     }
 }