Re: functions which read by prompting should not add additional chars to prompt string

[Stefan Monnier <monnier@iro.umontreal.ca>]

> IMO there is no need to add the default value, whatever it might be,
> to the prompt string.  As always, it is available via `M-n'.

That's the whole point of this calling convention for read-regexp: the
choice of whether to place the default in the prompt is centralized in
read-regexp, so it can easily be changed, instead of being duplicated in
each and every call to read-regexp (as is currently the case for pretty
much all other read-<foo> functions) which hard-codes the behavior and
renders it impossible to let users choose another behavior.

I.e. read-regexp's behavior is the right one, the other functions would
need to be adjusted to follow the same principle (tho doing it in
backward-compatible way is difficult).


        Stefan