clean a bit

Author: asukaminato0721

crates/hir-ty/src/infer/closure.rs

@@ -131,7 +131,7 @@ impl<'db> InferenceContext<'_, 'db> {
                         self.table.next_ty_var()
                     }
                     ClosureKind::Coroutine { kind: CoroutineKind::AsyncGen, .. } => {
-                        unimplemented!()
+                        todo!()
                     }
                     _ => unreachable!(),
                 };
@@ -176,7 +176,9 @@ impl<'db> InferenceContext<'_, 'db> {
                 let bound_yield_ty = match coroutine_kind {
                     CoroutineKind::Async => self.types.types.unit,
                     CoroutineKind::Gen => self.table.next_ty_var(),
-                    CoroutineKind::AsyncGen => unimplemented!(),
+                    CoroutineKind::AsyncGen => {
+                        todo!()
+                    }
                 };
                 // Compute all of the variables that will be used to populate the coroutine.
                 let resume_ty = self.table.next_ty_var();