bug#35885: 25.2; Few mistakes in Emacs Manual (+ proposals)

[Sebastian Urban]

I'm reopening this bug, because last time I unarchived it, it was
automatically archived after 28d.

Since TEXINFO.TEX ver. 2020-05-14, this:

> --- old/emacs.texi       2020-05-10 21:24:52.351021900 +0200
> +++ new/emacs.texi       2020-05-10 21:23:30.621478300 +0200
> @@ -99,10 +99,13 @@
>
>  @end titlepage
>
> +@evenheading @thispage @| @|
> +@oddheading @| @| @thispage
>
>  @summarycontents
>  @contents
>
> +@headings double
>
>  @ifnottex
>  @node Top

can be simplified to:

--8<---------------cut here---------------start------------->8---
--- old/emacs.texi
+++ new/emacs.texi
@@ -99,10 +99,13 @@

 @end titlepage

+@headings double

 @summarycontents
 @contents


 @ifnottex
 @node Top
--8<---------------cut here---------------end--------------->8---


S. U.