Fix Lock "compiler speclet" URL

Author: richardszalay

xml/System.Threading/Lock.xml

@@ -30,7 +30,7 @@ It is recommended to use the <xref:System.Threading.Lock.EnterScope%2A> method w
 
 :::code language="csharp" source="~/snippets/csharp/System.Threading/Lock/Overview/UsagePatterns.cs" id="Snippet1":::
 
-When using the C# `lock` keyword or similar to enter and exit a lock, the type of the expression must be precisely `System.Threading.Lock`. If the type of the expression is anything else, such as `Object` or a generic type like `T`, a different implementation that is not interchangeable can be used instead (such as <xref:System.Threading.Monitor>). For more information, see the relevant [compiler speclet](https://github.com/dotnet/csharplang/blob/main/proposals/lock-object.md).
+When using the C# `lock` keyword or similar to enter and exit a lock, the type of the expression must be precisely `System.Threading.Lock`. If the type of the expression is anything else, such as `Object` or a generic type like `T`, a different implementation that is not interchangeable can be used instead (such as <xref:System.Threading.Monitor>). For more information, see the relevant [compiler speclet](https://github.com/dotnet/csharplang/blob/main/proposals/csharp-13.0/lock-object.md).
 
 <xref:System.Threading.Thread.Interrupt%2A> can interrupt threads that are waiting to enter a lock. On Windows STA threads, waits for locks allow message pumping that can run other code on the same thread during a wait. Some features of the waits can be overridden by a custom <xref:System.Threading.SynchronizationContext>.