[doc] update rst (#470)

* update rst

* remove empty rst

docs/colossalai/colossalai.zero.sharded_model.utils.rst

+colossalai.zero.sharded\_model.utils
+====================================
+
+.. automodule:: colossalai.zero.sharded_model.utils
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.base_store.rst

+colossalai.zero.sharded\_optim.bookkeeping.base\_store
+======================================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping.base_store
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.bucket_store.rst

+colossalai.zero.sharded\_optim.bookkeeping.bucket\_store
+========================================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping.bucket_store
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.gradient_store.rst

+colossalai.zero.sharded\_optim.bookkeeping.gradient\_store
+==========================================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping.gradient_store
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.parameter_store.rst

+colossalai.zero.sharded\_optim.bookkeeping.parameter\_store
+===========================================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping.parameter_store
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.rst

+colossalai.zero.sharded\_optim.bookkeeping
+==========================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping
+   :members:
+
+
+.. toctree::
+   :maxdepth: 2
+
+   colossalai.zero.sharded_optim.bookkeeping.base_store
+   colossalai.zero.sharded_optim.bookkeeping.bucket_store
+   colossalai.zero.sharded_optim.bookkeeping.gradient_store
+   colossalai.zero.sharded_optim.bookkeeping.parameter_store
+   colossalai.zero.sharded_optim.bookkeeping.tensor_bucket

docs/colossalai/colossalai.zero.sharded_optim.bookkeeping.tensor_bucket.rst

+colossalai.zero.sharded\_optim.bookkeeping.tensor\_bucket
+=========================================================
+
+.. automodule:: colossalai.zero.sharded_optim.bookkeeping.tensor_bucket
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.rst

+colossalai.zero.sharded\_optim
+==============================
+
+.. automodule:: colossalai.zero.sharded_optim
+   :members:
+
+.. toctree::
+   :maxdepth: 2
+
+   colossalai.zero.sharded_optim.bookkeeping
+
+
+.. toctree::
+   :maxdepth: 2
+
+   colossalai.zero.sharded_optim.sharded_optim
+   colossalai.zero.sharded_optim.sharded_optim_v2

docs/colossalai/colossalai.zero.sharded_optim.sharded_optim.rst

+colossalai.zero.sharded\_optim.sharded\_optim
+=============================================
+
+.. automodule:: colossalai.zero.sharded_optim.sharded_optim
+   :members:

docs/colossalai/colossalai.zero.sharded_optim.sharded_optim_v2.rst

+colossalai.zero.sharded\_optim.sharded\_optim\_v2
+=================================================
+
+.. automodule:: colossalai.zero.sharded_optim.sharded_optim_v2
+   :members:

docs/colossalai/colossalai.zero.sharded_param.rst

+colossalai.zero.sharded\_param
+==============================
+
+.. automodule:: colossalai.zero.sharded_param
+   :members:
+
+
+.. toctree::
+   :maxdepth: 2
+
+   colossalai.zero.sharded_param.sharded_param
+   colossalai.zero.sharded_param.sharded_tensor

docs/colossalai/colossalai.zero.sharded_param.sharded_param.rst

+colossalai.zero.sharded\_param.sharded\_param
+=============================================
+
+.. automodule:: colossalai.zero.sharded_param.sharded_param
+   :members:

docs/colossalai/colossalai.zero.sharded_param.sharded_tensor.rst

+colossalai.zero.sharded\_param.sharded\_tensor
+==============================================
+
+.. automodule:: colossalai.zero.sharded_param.sharded_tensor
+   :members:

docs/colossalai/colossalai.zero.zero_redundancy_optimizer_level_2.rst

-colossalai.zero.zero\_redundancy\_optimizer\_level\_2
-=====================================================
-
-.. automodule:: colossalai.zero.zero_redundancy_optimizer_level_2
-   :members:

docs/colossalai/colossalai.zero.zero_redundancy_optimizer_level_3.rst

-colossalai.zero.zero\_redundancy\_optimizer\_level\_3
-=====================================================
-
-.. automodule:: colossalai.zero.zero_redundancy_optimizer_level_3
-   :members: