Extending emacs convention for first line

[Christopher Dimech <dimech@gmx.com>]

Emacs convention states that the format for the first line is

;;; filename --- description  -*- lexical-binding: t; -*-

Because at the times one does notice longer filenames and descriptions,
it would be favorable if the convention would be extended to handle longer
filenames and descriptions.

For instance, using ;;; to distinguish, with "lexical-binding" still written first.

;;; -*- lexical-binding: t; -*-

;;; filename

;;; description

Or some other way that would work nicely.