RE: `set-variable' should use :set

[Drew Adams]

> Sounds reasonable to me....
> 
> BTW, my vague impression is that `set-variable' is pretty 
> lightly used, maybe because it's not that much more convenient
> than just "M-: (setq..."
> 
> Making this change might make it a much more useful command...

That's also my vague impression.
And I agree that this might help.

However, I disagree that it is not that much more convenient than setq.  For one
thing, it respects the defcustom :type spec.  For another, it uses a proper
interactive spec.  The type-checking in particular is a win, IMO.

(FWIW, I use it often.)