bug#37878: [PATCH] Add auto-insert skeleton for ".dir-locals.el"

[Juri Linkov]

> Steps to reproduce:
> 0. emacs -Q
> 1. M-x auto-insert-mode
> 2. C-x C-f .dir-locals.el RET
>
> Result: The entire Emacs standard header gets inserted into the
> buffer, complete with author, copyright notice, provide-statement,
> etc.
> Expected result: Either don't insert anything or use a custom skeleton.
>
> Please find attached a proposed patch, which adds a skeleton for
> "dir-locals.el" to auto-insert-alist.  I believe it would make it
> easier for especially beginning Emacs users to use ".dir-locals.el".
> (Open the file, type M-x auto-insert, and voilá.)
>
> Any comments?

Good addition for someone who doesn't use add-dir-local-variable
that inserts this header.

BTW, please also add the same two lines to the header of
.dir-locals.el in Emacs repository.