Hide the implementation of Task (#22009)

The `Option<T>` within `Ready` is confusing and using `None` for it can
cause crashes. There was actually one instance of this!

Release Notes:

- N/A

crates/lsp/src/lsp.rs

@@ -443,7 +443,7 @@ impl LanguageServer {
                 let stderr_captures = stderr_capture.clone();
                 cx.spawn(|_| Self::handle_stderr(stderr, io_handlers, stderr_captures).log_err())
             })
-            .unwrap_or_else(|| Task::Ready(Some(None)));
+            .unwrap_or_else(|| Task::ready(None));
         let input_task = cx.spawn(|_| async move {
             let (stdout, stderr) = futures::join!(stdout_input_task, stderr_input_task);
             stdout.or(stderr)