Documentation for v0.1 version (#199)

* Adding Equations, solving typos
* improve _code.rst
* the team rst and restuctore index.rst
* fixing errors

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Co-authored-by: Dario Coscia <dariocoscia@dhcp-015.eduroam.sissa.it>

pina/model/multi_feed_forward.py

@@ -12,8 +12,9 @@ class MultiFeedForward(torch.nn.Module):
     together. The user has to define the `forward` method choosing how to
     combine the different FeedForward networks.
 
-    :param dict dff_dict: dictionary of FeedForward networks.
+    :param dict ffn_dict: dictionary of FeedForward networks.
     """
+
     def __init__(self, ffn_dict):
         super().__init__()