Change links to the newest examples

The current links are poiting to older examples on an individual
repo. This PR replaces those links with the PyTorch upstream
examples repo. Also, adding consistency in how examples are
referenced to point to the links.

Signed-off-by: Sahdev Zala <spzala@us.ibm.com>

intermediate_source/FSDP_adavnced_tutorial.rst

@@ -74,8 +74,8 @@ summarization using WikiHow dataset.  The main focus of this tutorial is to
 highlight different available features in FSDP that are helpful for training
 large scale model above 3B parameters. Also, we cover specific features for
 Transformer based models. The code for this tutorial is available in  `Pytorch
-Examples
-<https://github.com/HamidShojanazeri/examples/tree/FSDP_example/distributed/FSDP/>`__.
+examples
+<https://github.com/pytorch/examples/tree/main/distributed/FSDP/>`__.
 
 
 *Setup*
@@ -97,13 +97,13 @@ Please create a `data` folder, download the WikiHow dataset from `wikihowAll.csv
 `wikihowSep.cs <https://ucsb.app.box.com/s/7yq601ijl1lzvlfu4rjdbbxforzd2oag>`__,
 and place them in the `data` folder.  We will use the wikihow dataset from
 `summarization_dataset
-<https://github.com/HamidShojanazeri/examples/blob/FSDP_example/distributed/FSDP/summarization_dataset.py>`__.
+<https://github.com/pytorch/examples/blob/main/distributed/FSDP/summarization_dataset.py>`__.
 
 Next, we add the following code snippets to a Python script “T5_training.py”.
 
 .. note::
    The full source code for this tutorial is available in `PyTorch examples
-   <https://github.com/HamidShojanazeri/examples/tree/FSDP_example/distributed/FSDP>`__.
+   <https://github.com/pytorch/examples/tree/main/distributed/FSDP/>`__.
 
 1.3  Import necessary packages: