bug#23550: 25.0.93; cl.texi (for var on list by func): Fix documentation

[npostavs]

Tino Calancha <tino.calancha@gmail.com> writes:

> It might be useful rewrite that part to make it more clear, but i don't
> have a clear proposal.

Actually, looking at this some more, I think you should just apply your
patch that removes this stuff completely.  It's much clearer to write
that sort of example as

    (cl-loop for y = "lion" then (next-prey y)
             while y collect y)

And looking down the page, `for VAR = EXPR1 then EXPR2' is already
explained well enough (as well as the equivalence to the `for VAR on
LIST by FUNCTION' form).