Fix-multiple-loggers-typo (#16305)

Author: kamranisg

docs/source-pytorch/visualize/supported_exp_managers.rst

@@ -194,8 +194,8 @@ Access all loggers from any function (except the LightningModule *init*) to use
 
     class MyModule(LightningModule):
         def any_lightning_module_function_or_hook(self):
-            tensorboard_logger = self.logger.experiment[0]
-            wandb_logger = self.logger.experiment[1]
+            tensorboard_logger = self.loggers.experiment[0]
+            wandb_logger = self.loggers.experiment[1]
 
             fake_images = torch.Tensor(32, 3, 28, 28)