[Misc] update doc comment for send (#22026)

Signed-off-by: Andy Xie <andy.xning@gmail.com>

vllm/distributed/device_communicators/base_device_communicator.py

@@ -219,7 +219,7 @@ class DeviceCommunicatorBase:
         return output_tensor
 
     def send(self, tensor: torch.Tensor, dst: Optional[int] = None) -> None:
-        """Sends a tensor to the destination rank in a non-blocking way"""
+        """Sends a tensor to the destination rank in a blocking way"""
         """NOTE: `dst` is the local rank of the destination rank."""
         if dst is None:
             dst = (self.rank_in_group + 1) % self.world_size