Re: master 9ade7ea: Fix Eldoc problem when loading on Emacs 26.3

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> Maybe come up with a better idea, or maybe, like Stefan suggests, don't
>> make it an alias at all, just deprecate it and keep using it instead of
>> eldoc-documentation-strategy when we find it to be bound.
>
> That sort of works, but it forces extensions that do want to
> "Package-Require" eldoc to remember to unbind
> eldoc-documentation-function if they are loaded on older Emacs versions,
> which is undesirable.

Maybe use a rule like:

    (if (and (buffer-local-p 'eldoc-documentation-function)
             (not (buffer-local-p 'eldoc-documentation-functions)))
        <Use `eldoc-documentation-function`>
      <Use `eldoc-documentation-functions`>


-- Stefan