bug#29412: 27.0.50; dired-toggle-read-only should (at some point!) check that the direcory is writeable

[Juri Linkov]

>> Then maybe better would be to ask a y-or-n question
>> whether the user still wants to edit the unwritable buffer.
>
> I disagree.  This should be handled _exactly_ the
> same way we handle a buffer for a file that is
> read-only.  I see no argument why we should treat
> a directory buffer different from a file buffer.

Asking a y-or-n question is _exactly_ what
'C-x C-q' does in wdired, i.e. after typing
'C-x C-q' (wdired-exit) it asks a question:

  Buffer modified; save changes? (y or n) 

So now entering wdired mode does the same thing with
'C-x C-q' (dired-toggle-read-only):

  Directory isn't writable; edit anyway? (y or n)