Remove the paramstuff word

The chew "paramstuff" word has been a no-op since:

    commit c58b95236ce4c9345c4fa76e7ef16762e5229380
    Author: Alan Modra <amodra@gmail.com>
    Date:   Sun Jun 29 10:06:40 2003 +0000

	Convert to C90 and a few tweaks.

Remove it and its one use.

2023-02-07  Tom Tromey  <tom@tromey.com>

	* doc/proto.str (SYNOPSIS): Don't use paramstuff.
	* doc/chew.c (paramstuff): Remove.
	(main): Don't add paramstuff intrinsic.