fix(networks): render LayerNormNd shape notation as literals

The channels-first and channels-last shapes in the class docstring were
written as bare tuples, so docutils read the leading asterisk of
`*spatial` as the start of inline emphasis and the docs build failed on
the resulting warning. Mark them up as inline literals instead.

Signed-off-by: VenkateswarluNagineni <venkates2002@tamu.edu>

Author: VenkateswarluNagineni

monai/networks/layers/layer_norm_nd.py

@@ -20,8 +20,8 @@ class LayerNormNd(nn.Module):
     Layer normalization over the channel dimension of a channels-first tensor.
 
     `torch.nn.LayerNorm` normalizes over the trailing dimensions, so it expects a channels-last layout
-    such as (batch, *spatial, channel). Convolutional feature maps in MONAI are channels-first,
-    (batch, channel, *spatial), and this module normalizes those over the channel dimension only,
+    such as ``(batch, *spatial, channel)``. Convolutional feature maps in MONAI are channels-first,
+    ``(batch, channel, *spatial)``, and this module normalizes those over the channel dimension only,
     for any number of spatial dimensions.
 
     Args: