Why does texinfo-make-menu append trailing whitespace?

[Alan Mackenzie]

Emacs 21.1.

I'm updating a file.texi using Texinfo-mode.  When I do C-c C-u <ret> to
update a menu, the resulting menu has trailing spaces after each item.
There wasn't any such trailing spaces beforehand.

I don't like this.  Is it a bug, or is there some reason for this
trailing space?

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").