Re: `aset` on strings, changing the size in bytes

[Stefan Monnier]

> I meant to make aset cons a new string when it turns out the original
> one's data is too small to include the new contents.

`aset` is documented to return NEWELT, so what could it do with the
newly cons'd string?
We'd have to change `aset` so it returns this newly cons'd string, but
that would also be a backward incompatible change.  Better introduce
a new function `sset` for it.


        Stefan