Hello again,

Thanks for the feedback.  I agree with the will of allowing more freedom.

I joined a replacement patch with the different route that this is now
taking,
namely the removal of `eldoc--format-doc-buffer' in favor of
`eldoc-render-documentation'.  Is that closer to what you had in mind?

There's an issue however with the `-hr` format function that won't work with
terminal-based Emacs due to `:strike-through` apparently not supported
there.  I
was wondering whether a simple mention of that limitation in the docstring
would
be enough?  Terminal-based users would still be able to use the default
format
function.  Regarding the `:extend` keyword not being supported on 26, I
think
a better way than conditionally add it would be to provide a second `-hr`
formatting function that relies on something that is supported on 26 ie.
overlay.  Although I have little to no experience with overlays so I'm not
sure
what would be the preferred way of making a horizontal divider.
Furthermore, it
shouldn't break when the render function is used to return a string.
-- 
Mathieu Marques