[DeviceMesh] init_device_mesh dosctring update to include one d mesh initialization (#107805)

As title.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/107805
Approved by: https://github.com/fduwjj, https://github.com/wanchaol
diff --git a/torch/distributed/_tensor/device_mesh.py b/torch/distributed/_tensor/device_mesh.py
index 276d79d..2ac36bb 100644
--- a/torch/distributed/_tensor/device_mesh.py
+++ b/torch/distributed/_tensor/device_mesh.py
@@ -381,6 +381,7 @@
         >>> # xdoctest: +SKIP
         >>> from torch.distributed._tensor.device_mesh import init_device_mesh
         >>>
+        >>> one_d_mesh = init_device_mesh("cuda", mesh_shape=(8,))
         >>> two_d_mesh = init_device_mesh("cuda", mesh_shape=(2, 8), mesh_dim_names=("dp", "tp"))
     """
     if mesh_dim_names is not None and len(mesh_shape) != len(mesh_dim_names):