Might be good for newcomers to read what N means (#41851)

Summary: Pull Request resolved: pytorch/pytorch#41851

Reviewed By: izdeby

Differential Revision: D22703602

Pulled By: mrshenli

fbshipit-source-id: 44905f43cdf53b38e383347e5002a28c9363a446

torch/nn/functional.py

@@ -1667,7 +1667,7 @@ def linear(input, weight, bias=None):
 
     Shape:
 
-        - Input: :math:`(N, *, in\_features)` where `*` means any number of
+        - Input: :math:`(N, *, in\_features)` N is the batch size, `*` means any number of
           additional dimensions
         - Weight: :math:`(out\_features, in\_features)`
         - Bias: :math:`(out\_features)`