docs(mge/module): add Module.state_dict docstring

GitOrigin-RevId: 424ec791d7eda63d2835154d3d2e985a8915f7d5

imperative/python/megengine/module/module.py

@@ -452,6 +452,7 @@ class Module(metaclass=ABCMeta):
         return offset
 
     def state_dict(self, rst=None, prefix="", keep_var=False):
+        r"""Returns a dictionary containing whole states of the module."""
         _rst = self._state_dict(rst=rst, prefix=prefix, keep_var=keep_var)
         rst = OrderedDict()
         XNorm_typeclass = _get_XNorm_typeclass()