Add __all__ to most modules beginning with 'n', 'o' and 'p' (#7345)

stdlib/pydoc.pyi

@@ -4,6 +4,8 @@ from reprlib import Repr
 from types import MethodType, ModuleType, TracebackType
 from typing import IO, Any, AnyStr, Callable, Container, Mapping, MutableMapping, NoReturn, TypeVar
 
+__all__ = ["help"]
+
 # the return type of sys.exc_info(), used by ErrorDuringImport.__init__
 _Exc_Info = tuple[type[BaseException] | None, BaseException | None, TracebackType | None]