fix typo (#3149)

Co-authored-by: Svetlana Karslioglu <svekars@meta.com>

Author: gameofdimension

recipes_source/distributed_device_mesh.rst

@@ -164,7 +164,7 @@ DeviceMesh allows users to slice child mesh from the parent mesh and re-use the
 
     # Users can access the underlying process group thru `get_group` API.
     replicate_group = hsdp_mesh["replicate"].get_group()
-    shard_group = hsdp_mesh["Shard"].get_group()
+    shard_group = hsdp_mesh["shard"].get_group()
     tp_group = tp_mesh.get_group()