bug#44748: [PATCH] New section on package initialization; document quickstart

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Kangas <stefan@marxist.se>
> Date: Thu, 19 Nov 2020 17:00:18 -0800
> Cc: monnier@iro.umontreal.ca
> 
> Please find attached a patch to add a new section on package
> initialization to the user manual, and to document package-quickstart.
> 
> Thoughts?

Does adding 2 short paragraphs justify yet another node?  The original
text is 125 lines long, not too long IMO.

> diff --git a/doc/emacs/package.texi b/doc/emacs/package.texi
> index 4981dd50c7..3e9be39475 100644
> --- a/doc/emacs/package.texi
> +++ b/doc/emacs/package.texi
> @@ -48,6 +48,7 @@ Packages
>  * Package Menu::         Buffer for viewing and managing packages.
>  * Package Statuses::     Which statuses a package can have.
>  * Package Installation:: Options for package installation.
> +* Package Initialization:: How packages are initialized.
>  * Package Files::        Where packages are installed.
>  @end menu

When you add nodes, you need to update the detailed menu in emacs.texi
as well.

> +@findex package-quickstart-refresh
> +@vindex package-quickstart
> +  If you have many packages installed, you can improve startup times
> +by setting the user option @code{package-quickstart} to @code{t}.
> +This requires you to manually run the command
> +@code{package-quickstart-refresh} when the activations need to be
> +changed, such as when you change the value of
> +@code{package-load-list}.

This text doesn't explain what the quick start does.  Perhaps saying
what will happen if the user forgets to manually run that command
(error messages? signs of incorrect behavior?) would suffice.
Otherwise this text sounds like some black magic, and that is not a
good thing for a user manual.

Thanks.