bug#18253: 24.4.50; doc string of `remq': correct it per the doc of `remove'

[Stefan Monnier]

>  If the only elements in LIST that are `eq' to ELT occur before any
>  other elements then a copy is not made: the tail after the last such
>  occurrence is returned.
> Whatever language we choose, it should be precise wrt what the behavior
> is.

I don't see a need for precision.  It should just say that the returned list
may share some elements with the original argument, but that no element
was modified by side-effect.


        Stefan