bug#27230: eldoc doc

[Dmitry Gutov <dgutov@yandex.ru>]

On 6/25/17 10:47 PM, Charles A. Roelli wrote:

> FORMAT-STRING (or nil, if not given) is stored in
> `eldoc-last-message'.  If ARGS are given, FORMAT-STRING is first
> formatted through `format-message'.

I wonder if we ever call this function with more than one argument. If 
not, the code and the doc call for simplification. We can avoid 
advertising this possibility, at least.

> If `eldoc-last-message' is non-nil, display it using
> `eldoc-message-function'.  If it is nil, clear the echo area if
> there was recently a message from ElDoc there.

I think this needlessly prioritizes the implementation over the 
intention. And the latter is to display whatever the documentation 
function returns (if non-nil). Saving to eldoc-last-message is 
secondary, and can be mentioned later.

> Return `eldoc-last-message'."

This is probably non-essential, and we can avoid mentioning it.