WebSocket KeepAlive section improvements

[CarnaViire]

Describe the issue or suggestion

Follow-ups from #44611

• 1. Use xrefs (WebSocket Keep-Alive #44611 (comment), WebSocket Keep-Alive #44611 (comment), WebSocket Keep-Alive #44611 (comment))

  • 1.1.

    docs/docs/fundamentals/networking/websockets.md

    Lines 109 to 116 in 3b05c5f

    	1. Keep-Alive is **OFF**, if
    	- `KeepAliveInterval` is `TimeSpan.Zero` or `Timeout.InfiniteTimeSpan`
    	2. **Unsolicited PONG**, if
    	- `KeepAliveInterval` is a positive finite `TimeSpan`, -AND-
    	- `KeepAliveTimeout` is `TimeSpan.Zero` or `Timeout.InfiniteTimeSpan`
    	3. **PING/PONG**, if
    	- `KeepAliveInterval` is a positive finite `TimeSpan`, -AND-
    	- `KeepAliveTimeout` is a positive finite `TimeSpan`

    It would be better to use <xref> here instead of code blocks.

  • 1.2.

    docs/docs/fundamentals/networking/websockets.md

    Line 169 in 3b05c5f

    > Currently, `WebSocket` ONLY processes incoming frames while there's a `ReceiveAsync` pending.

    > Currently, `WebSocket` ONLY processes incoming frames while there's a <xref:System.Net.WebSockets.WebSocket.ReceiveAsync%2A> task pending.

  • 1.3.

    docs/docs/fundamentals/networking/websockets.md

    Line 156 in 3b05c5f

    If the timeout elapses, an outstanding `ReceiveAsync` throws an `OperationCanceledException`:

    If the timeout elapses, an outstanding <xref:System.Net.WebSockets.WebSocket.ReceiveAsync%2A> throws an <xref:System.OperationCanceledException>:
    

• 2. Reword to clarify this is an implication (WebSocket Keep-Alive #44611 (comment))

  docs/docs/fundamentals/networking/websockets.md

  Line 122 in 3b05c5f

  If you want to switch to the PING/PONG strategy, overriding <xref:System.Net.WebSockets.ClientWebSocketOptions.KeepAliveTimeout?displayProperty=nameWithType> is enough:

  Would be good suggest that this is an implication of the behavior described before.

  As a result, overriding <xref:System.Net.WebSockets.ClientWebSocketOptions.KeepAliveTimeout?displayProperty=nameWithType> is enough to switch to the PING/PONG strategy if you keep the default value for <xref:System.Net.WebSockets.WebSocket.DefaultKeepAliveInterval?displayProperty=nameWithType>:
  

• 3. Reword sentence conjunctions (WebSocket Keep-Alive #44611 (comment))

  docs/docs/fundamentals/networking/websockets.md

  Line 172 in 3b05c5f

  > If you want to use Keep-Alive Timeout, it's _crucial_ that PONG responses are _promptly processed_. Even if the remote endpoint is alive and properly sends the PONG response, but the `WebSocket` isn't processing the incoming frames, the Keep-Alive mechanism can issue a "false-positive" Abort. This problem can happen if the PONG frame is never picked up from the transport stream before the timeout elapsed.

  > If you want to use Keep-Alive Timeout, it's _crucial_ that PONG responses are _promptly processed_. Even when the remote endpoint is alive and properly sends the PONG response, if the `WebSocket` isn't processing the incoming frames, the Keep-Alive mechanism can issue a "false-positive" Abort. This problem can happen if the PONG frame is never picked up from the transport stream before the timeout elapsed.
  

• 4. Fix typo (Minor grammar issue in websocket docs. #44952)

  There is a sentence that starts about two thirds of the way through the "Keep-Alive strategies" section of the article that begins "They sent regularly with KeepAliveInterval intervals...". Nothing major but I think "They sent" should probably be "They are sent".