Customized read-from-minibuffer in query-replace

[Tobias C. Rittweiler]

The function `query-replace-read-from' and `query-replace-read-to'
directly call `read-from-minibuffer'. I'd like to customize the way the
input is read to use `completing-read' instead at a specialized
application of query-replace.

I have a patch which introduces a variable
`query-replace-read-from-minibuffer-function' which is called at the
appropriate places. 

That patch is fairly simple -- do you think it would need an copyright
assignment?

I'm not including the patch file so if it does require one, someone may
just say "Uh, that's so simple, I'll do it right away." I'm sure if that
was so easy if he looked at the patch before. :-)

  -T.