bug#14979: 24.3; Feature Request: query-replace-backward

[Drew Adams]

> > no prefix M-% - normal non-word replacement forwards
> > C-u M-% - word replacement forwards
> > M-- M-% (negative argument) - normal non-word replacement backwards
> > ??? - word replacement backwards
> 
> no prefix M-% - normal non-word replacement forwards
> C-u M-% - word replacement forwards
> M-0 M-% - normal non-word replacement backwards
> M-- M-% - word replacement backwards

I vote against using a prefix arg for anything like this.  There are
better things to use a prefix arg for.

Instead, either choose a different key altogether for backward q-r or
do not bind a key for it at all.

Just one opinion.


FWIW, I bind `M-%' to a command that rolls together these q-r
behaviors:

* No prefix arg: string q-r (like vanilla `query-replace')
* Negative prefix arg: regexp q-r
* Non-negative prefix arg: word q-r (like vanilla `query-replace')