bug#72829: describe-function NEWS* scraper override

[Stefan Kangas <stefankangas@gmail.com>]

Mattias Engdegård <mattias.engdegard@gmail.com> writes:

> `describe-function` sometimes gives incorrect information about when
> certain functions were first introduced. NEWS.unknown can be used to
> fix some problems but it only works in one direction and is unable to
> help when a function name appears too early.
>
> A robust solution would be to make NEWS* use a mark-up like
> @function{some-name} instead of just 'some-name' but meanwhile, here
> is a simple patch that replaces NEWS.unknown with a more structured
> file. This fixes the case for `always`.

This is a welcome change.

For symbols that are in symbol-releases.eld, which means we are actually
sure about the addition, shouldn't the help text be changed from

    Probably introduced at or before Emacs version XX.Y.

to something more like

    Added in Emacs version XX.Y.

?  I mean, we should be sure about what we put in that file, presumably.

Steve Purcell (in Cc) has been maintaining a relatively complete symbol
to version database here:

    https://github.com/purcell/package-lint/blob/master/data/stdlib-changes

Note that his version keeps track of also of `feature`s, and not just
additions but removals as well.  It would be nice if our version could
be extended to do the same.  Perhaps Steve has some code or ideas that
he would be willing to contribute.