add-file-local-variable-prop-line

[chad]

I'm writing a convenience function to set the major mode for some
files, and I'd like to also set the `-*-' indicator to the desired
mode.  When I was doing it by hand, I was using syntax like:

    -*- org -*-

on the initial line, rather than the longer:

    -*- mode: org; -*-

format.  I assumed that there would be a function for this, and there
is: add-file-local-variable-prop-line will do what I want, but doesn't
seem to support the simpler syntax.  I can make the simpler syntax
work, but I wonder if there is some policy change or feature that
really prefers the more explicit syntax.

Thanks!