bug#41531: 28.0.50; proper Eldoc async support

["João Távora" <joaotavora@gmail.com>]

Andrii Kolomoiets <andreyk.mad@gmail.com> writes:

> Dmitry Gutov <dgutov@yandex.ru> writes:
>> On 04.06.2020 19:20, Andrii Kolomoiets wrote:
>>> 3. That IMO useless "...truncated, see*help*  buffer" message is moved
>>> to Eldoc.  Do we really need to show this message every time?  That one
>>> last line can be used to show additional documentation.
>> The truncation can be indicated as ellipsis at the end of the (first)
>> line. Maybe ellipsis in parentheses (...).
>
> Good idea.

I think is is easily missed, and will not inform of the keybinding for
`eldoc-doc-buffer'.  But it's clearly better than nothing for the
strictly-one-line people.

>> Whether to use multiple lines of not, seems like individual preference.
>
> Absolutely.  That's why there are customizable variables so anyone can
> tweak behavior to their likes.  Current version of Eglot pays attention
> to the eldoc-echo-area-use-multiline-p variable and proposed one do
> not.

It does not because most of that variable (except for the very special
"truncate-sym-name-if-fit" value) is now handled in eldoc.el.  Modulo
bugs, of course, which I will endeavour to fix.  I also agree, of course
this is individual preference.