Issue #11014: Make 'filter' argument in tarfile.Tarfile.add() into a
keyword-only argument.  The preceding positional argument was deprecated,
so it made no sense to add filter as a positional argument.

(Patch reviewed by Brian Curtin and Anthony Long.)
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
index d7fbf39..d578a79 100644
--- a/Doc/library/tarfile.rst
+++ b/Doc/library/tarfile.rst
@@ -370,19 +370,20 @@
       and :meth:`close`, and also supports iteration over its lines.
 
 
-.. method:: TarFile.add(name, arcname=None, recursive=True, exclude=None, filter=None)
+.. method:: TarFile.add(name, arcname=None, recursive=True, exclude=None, *, filter=None)
 
-   Add the file *name* to the archive. *name* may be any type of file (directory,
-   fifo, symbolic link, etc.). If given, *arcname* specifies an alternative name
-   for the file in the archive. Directories are added recursively by default. This
-   can be avoided by setting *recursive* to :const:`False`. If *exclude* is given,
-   it must be a function that takes one filename argument and returns a boolean
-   value. Depending on this value the respective file is either excluded
-   (:const:`True`) or added (:const:`False`). If *filter* is specified it must
-   be a function that takes a :class:`TarInfo` object argument and returns the
-   changed :class:`TarInfo` object. If it instead returns :const:`None` the :class:`TarInfo`
-   object will be excluded from the archive. See :ref:`tar-examples` for an
-   example.
+   Add the file *name* to the archive. *name* may be any type of file
+   (directory, fifo, symbolic link, etc.). If given, *arcname* specifies an
+   alternative name for the file in the archive. Directories are added
+   recursively by default. This can be avoided by setting *recursive* to
+   :const:`False`. If *exclude* is given, it must be a function that takes one
+   filename argument and returns a boolean value. Depending on this value the
+   respective file is either excluded (:const:`True`) or added
+   (:const:`False`). If *filter* is specified it must be a keyword argument.  It
+   should be a function that takes a :class:`TarInfo` object argument and
+   returns the changed :class:`TarInfo` object. If it instead returns
+   :const:`None` the :class:`TarInfo` object will be excluded from the
+   archive. See :ref:`tar-examples` for an example.
 
    .. versionchanged:: 3.2
       Added the *filter* parameter.