fix warnings

Author: BillWagner

docs/csharp/language-reference/compiler-messages/cs4004.md

@@ -1,7 +1,7 @@
 ---
 description: "Compiler Error CS4004"
 title: "Compiler Error CS4004"
-ms.date: 07/01/20242
+ms.date: 07/01/2024
 f1_keywords:
   - "CS4004"
 helpviewer_keywords:

docs/csharp/specification/toc.yml

@@ -184,7 +184,7 @@ items:
     - name: Lock object semantics
       href: ../../../_csharplang/proposals/lock-object.md
     - name: Allow `ref` and `unsafe`
-      href: ../../_csharplang/proposals/ref-unsafe-in-terators-async.md 
+      href: ../../../_csharplang/proposals/ref-unsafe-in-terators-async.md 
   - name: Namespaces
     items:
     - name: File scoped namespaces

docs/csharp/whats-new/csharp-13.md

@@ -74,7 +74,7 @@ var countdown = new TimerRemaining()
 
 The preceding example creates an array that counts down from 9 to 0. In versions before C# 13, the `^` operator can't be used in an object initializer. You need to index the elements from the front.
 
-# `ref` and `unsafe` in iterators and `async` methods
+## `ref` and `unsafe` in iterators and `async` methods
 
 Before C# 13, iterator methods (methods that use `yield return`) and `async` methods couldn't declare local `ref` variables, nor could they have an `unsafe` context.