Fix reference to dcp in loading example (#2972)

* Fix reference to DCP
* Keep import style as saving

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Co-authored-by: Iris Z <31293777+wz337@users.noreply.github.com>

Author: angerrp

recipes_source/distributed_checkpoint_recipe.rst

@@ -289,7 +289,7 @@ the intent is to save or load in "non-distributed" style, meaning entirely in th
     import os
 
     import torch
-    import torch.distributed.checkpoint as DCP
+    import torch.distributed.checkpoint as dcp
     import torch.nn as nn