Update on "[FSDP] Clarify CPU offload implicitly in reshard_doc"

Per title

Differential Revision: [D44812344](https://our.internmc.facebook.com/intern/diff/D44812344/)

[ghstack-poisoned]

torch/distributed/fsdp/flat_param.py

@@ -1489,7 +1489,7 @@ def reshard(self, free_unsharded_flat_param: bool):
         parameter if ``free_unsharded_flat_param`` and switching to using the
         sharded flat parameter. Note that this also implicitly offloads
         the sharded flat parameter (if CPU offload is enabled) by pointing
-        it to the local_shard attribute which resides on CPU.
+        it to the ``_local_shard`` attribute which resides on CPU.
         """
         # Switch to the sharded `FlatParameter` before freeing to prevent
         # "use-after-free"-type bugs with external profiling tools, where for