Fix comment

Author: aerooneqq

compiler/rustc_ast_lowering/src/delegation.rs

@@ -181,7 +181,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
 
         let sig_id = self.tcx.delegations_resolutions(()).get(&self.owner.def_id).copied();
 
-        // Delegation can be unresolved in illegal places such as function bodies in extern blocks (see #151356)
+        // Delegation can be missing from the `delegations_resolutions` table
+        // in illegal places such as function bodies in extern blocks (see #151356).
         let Some(Ok(sig_id)) = sig_id else {
             self.dcx().span_delayed_bug(
                 span,