Fix outdated docs follow up (#1266)

* save_top_k

* num_gpus

* print_nan_grads fix leftovers

* undo doctest removal

docs/source/weights_loading.rst

@@ -35,7 +35,7 @@ To modify the behavior of checkpointing pass in your own callback.
     # DEFAULTS used by the Trainer
     checkpoint_callback = ModelCheckpoint(
         filepath=os.getcwd(),
-        save_best_only=True,
+        save_top_k=True,
         verbose=True,
         monitor='val_loss',
         mode='min',

pytorch_lightning/core/lightning.py

@@ -799,7 +799,7 @@ class LightningModule(ABC, GradInformation, ModelIO, ModelHooks):
 
         Args:
             proc_rank: The current process rank within the node.
-            world_size: Number of GPUs being use across all nodes. (num_nodes*nb_gpu_nodes).
+            world_size: Number of GPUs being use across all nodes. (num_nodes * num_gpus).
 
         Examples:
             .. code-block:: python

pytorch_lightning/trainer/__init__.py

@@ -195,7 +195,7 @@ Example::
     # default used by the Trainer
     checkpoint_callback = ModelCheckpoint(
         filepath=os.getcwd(),
-        save_best_only=True,
+        save_top_k=True,
         verbose=True,
         monitor='val_loss',
         mode='min',
@@ -595,12 +595,11 @@ Example::
 print_nan_grads
 ^^^^^^^^^^^^^^^
 
-Prints gradients with nan values
+.. warning:: .. deprecated:: 0.7.2.
 
-Example::
+    Has no effect. When detected, NaN grads will be printed automatically.
+    Will remove 0.9.0.
 
-    # default used by the Trainer
-    trainer = Trainer(print_nan_grads=False)
 
 process_position
 ^^^^^^^^^^^^^^^^