bug#3370: 23.0.94; `comment-region' indents comment chars inappropriately

[Chong Yidong]

> > In buffer *scratch*, type this: SPC SPC ` a b c d e f ' RET
> >
> > Select the line, including the newline at its end: `M-< C-SPC C-n'.
> > M-x comment-region
> > 
> > In Emacs 23, this is the result:
> > 
> >   ;; `abcdef'
> > 
> > In all previous versions of Emacs, the comment chars are inserted at
> > the start of the line - they are not indented two spaces

> Wrong.  The behavior is identical in Emacs 22.

Aha, I was mistaken.  Sorry for the confusion.

The default for `comment-style' has been changed, it is no longer
`plain'.  See Richard's 2007-10-26 changing it to `indent-or-tripe', and
Dan's 2008-12-18 change making it `indent' (Bug#1153).

This should have been documented in NEWS; I'll do that.