bug#35021: M-^ (delete-indentation) doesn't work without a mark present

[Eli Zaretskii]

> From: "Basil L. Contovounesios" <contovob@tcd.ie>
> Date: Wed, 27 Mar 2019 16:09:14 +0000
> Cc: 35021@debbugs.gnu.org, Stephen Leake <stephen_leake@stephe-leake.org>,
>       Łukasz Stelmach <stlman@poczta.fm>
> 
> > From a clean `emacs -Q` start:
> >
> > 1. Move point up to the bottom line of the *scratch* buffer comments
> > 2. Type M-^ (or M-x delete-indentation)
> > 3. Observe the following message in the minibuffer:
> >      The mark is not set now, so there is no region
> 
> This is because delete-indentation is currently using the 'r'
> interactive code, which barfs if the region is inactive.
> 
> I attach a patch which fixes this and also updates the entry for
> delete-indentation in the Elisp manual.  Is it acceptable?

Looks OK to me, please push.  Alex, this will also solve your bug
report, right?  If now, why not?

Thanks.