gh-84116: Docs: Document help and aliases for argparse.add_parser()

Doc/library/argparse.rst

@@ -1672,9 +1672,24 @@ Sub-commands
    :class:`ArgumentParser` supports the creation of such subcommands with the
    :meth:`!add_subparsers` method.  The :meth:`!add_subparsers` method is normally
    called with no arguments and returns a special action object.  This object
-   has a single method, :meth:`~_SubParsersAction.add_parser`, which takes a
-   command name and any :class:`!ArgumentParser` constructor arguments, and
-   returns an :class:`!ArgumentParser` object that can be modified as usual.
+   has a single method, :meth:`~_SubParsersAction.add_parser`:
+
+   .. method:: _SubParsersAction.add_parser(name, *, help=None, aliases=None, **kwargs)
+
+      Creates and returns a new :class:`!ArgumentParser` object for the
+      subcommand *name*.
+
+      :param name: The name of the sub-command.
+      :param help: A short description for this sub-command. If provided,
+                  it will be listed next to the command in the main
+                  parser's help message (e.g., ``PROG --help``).
+      :param aliases: A list or sequence of strings that can be used as
+                     alternative names for this sub-command (e.g., ``aliases=['r']``
+                     for a ``'run'`` command).
+      :param kwargs: All other keyword arguments are passed directly to the
+                     :class:`!ArgumentParser` constructor.
+
+      This returned :class:`!ArgumentParser` object can be modified as usual.
 
    Description of parameters:
 

Misc/NEWS.d/next/Documentation/2025-10-25-14-08-42.gh-issue-84116.lKcoHw.rst

@@ -0,0 +1,3 @@
+Document ``help`` and ``aliases`` parameters for
+:meth:`argparse._SubParsersAction.add_parser` in the :mod:`argparse`
+documentation.