message: fix a typo in nhwc.md
diff: @@ -74,7 +74,7 @@ Better to explain the concepts here with a diagram, the **dotted lines** indicat
  Before moving on, I feel it is necessary to explain how PyTorch organizes tensors in memory - the **layout**. Here we only focus on **dense** tensors, skip 'coo' layout of **sparse** tensor.
  -The question itself can be reinterpreted as for a tensor of size <N, C, H, W>, how does PyTorch accesses the element with index <n, w, h, w> from memory, the answer is **stride**:
  +The question itself can be reinterpreted as for a tensor of size <N, C, H, W>, how does PyTorch accesses the element with index <n, c, h, w> from memory, the answer is **stride**:
  ```
  tensor: <N, C, H, W>
  index: <n, c, h, w>
  