bug#50279: 28.0.50; ffap-file-finder customization no longer works

[Bob Rogers]

   I have a long-standing customization to ffap-file-finder which offers
external applications depending on file extension that is broken by the
following commit:

    commit 253b36bd40d1b342cdda09b0bee183788120f67e
    Author: dickmao <none>
    Date:   Tue Aug 3 12:02:48 2021 -0400

        ffap ido accommodation

        Now that ffap-file-finder can be ido-find-file, the
        noninteractive portion of find-file-at-point cannot
        assume ffap-file-finder always takes an argument
        (ido-find-file does not).

        * lisp/ffap.el (find-file-at-point): Do not call ffap-file-finder.
        * test/lisp/ffap-tests.el (ffap-ido-mode): Test it.

The essence of the change is that it does find-file at the critical
point instead of funcalling ffap-file-finder.  I assume that breaking
such extensions was not the intent, as it is an incompatible change to a
defcustom variable, and there is no associated NEWS entry.

                                        -- Bob Rogers
                                           http://www.rgrjr.com/