bug#31052: 26.0.91; Improve documentation of inline-letevals

[Eli Zaretskii]

> From: Gemini Lasswell <gazally@runbox.com>
> Date: Tue, 03 Apr 2018 17:33:31 -0700
> 
> I just got acquainted with inline-letevals and found its description
> in the Elisp manual confusing because the purpose of the macro is not
> stated, and it is described as similar to 'let' without mention of an
> important difference in what happens to the elements of the bindings
> list which are symbols.
> 
> Here's a patch to functions.texi where I've attempted to clarify the
> description.

Thanks, but your text left me confused, perhaps because it mixes the
details of the syntax and semantics with the explanation of why and
how to use them, and what is the result of such usage.  These should
be generally kept separate for clarity.

How about if you first tell informally what information is missing
from the original text, and then we see how to augment that by adding
the missing bits?