Replace draft WebSocket RFC with final RFC 6455 in API documentation (#11982)

Author: Copilot

xml/System.Net.WebSockets/WebSocket.xml

@@ -185,15 +185,15 @@ Exactly one send and one receive is supported on each <xref:System.Net.WebSocket
         <param name="closeStatus">Indicates the reason for closing the WebSocket connection.</param>
         <param name="statusDescription">Specifies a human readable explanation as to why the connection is closed.</param>
         <param name="cancellationToken">The token that can be used to propagate notification that operations should be canceled.</param>
-        <summary>Closes the WebSocket connection as an asynchronous operation using the close handshake defined in the <see href="https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-06">WebSocket protocol specification</see> section 7.</summary>
+        <summary>Closes the WebSocket connection as an asynchronous operation using the close handshake defined in the <see href="https://datatracker.ietf.org/doc/html/rfc6455">WebSocket protocol specification</see>, section 7.</summary>
         <returns>The task object representing the asynchronous operation.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
  This operation will not block. The returned <xref:System.Threading.Tasks.Task> object will complete after the WebSocket has been closed.  
   
- This method closes the WebSocket connection using the close handshake defined in the [WebSocket protocol specification](https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-06) section 7.  
+ This method closes the WebSocket connection using the close handshake defined in the [WebSocket protocol specification](https://datatracker.ietf.org/doc/html/rfc6455), section 7.  
   
  ]]></format>
         </remarks>
@@ -251,7 +251,7 @@ Exactly one send and one receive is supported on each <xref:System.Net.WebSocket
         <param name="closeStatus">Indicates the reason for closing the WebSocket connection.</param>
         <param name="statusDescription">Allows applications to specify a human readable explanation as to why the connection is closed.</param>
         <param name="cancellationToken">The token that can be used to propagate notification that operations should be canceled.</param>
-        <summary>Initiates or completes the close handshake defined in the <see href="https://tools.ietf.org/html/draft-ietf-hybi-thewebsocketprotocol-06">WebSocket protocol specification section 7</see>.</summary>
+        <summary>Initiates or completes the close handshake defined in the <see href="https://datatracker.ietf.org/doc/html/rfc6455">WebSocket protocol specification</see>, section 7.</summary>
         <returns>The task object representing the asynchronous operation.</returns>
         <remarks>
           <format type="text/markdown"><![CDATA[