add NotebookNotary to NotebookApp's class list

adds it to help output and config files

IPython/html/notebookapp.py

@@ -83,6 +83,7 b' from IPython.kernel.zmq.kernelapp import ('
     kernel_flags,
     kernel_aliases,
 )
+from IPython.nbformat.sign import NotebookNotary
 from IPython.utils.importstring import import_item
 from IPython.utils.localinterfaces import localhost
 from IPython.utils import submodule
@@ -311,7 +312,7 b' class NotebookApp(BaseIPythonApplication):'
     examples = _examples
     
     classes = IPythonConsoleApp.classes + [MappingKernelManager, NotebookManager,
-        FileNotebookManager]
+        FileNotebookManager, NotebookNotary]
     flags = Dict(flags)
     aliases = Dict(aliases)