bug#67687: Feature request: automatic tags management

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Kangas <stefankangas@gmail.com>
> Date: Sat, 30 Dec 2023 12:56:38 -0800
> Cc: eskinjp@gmail.com, 67687@debbugs.gnu.org, 
> 	Michael Albinus <michael.albinus@gmx.de>
> 
>  @menu
>  * Tag Syntax::          Tag syntax for various types of code and text files.
> -* Create Tags Table::   Creating a tags table with @command{etags}.
> +* Update Tags Table::   Creating a tags table automatically.
> +* Create Tags Table::   Creating a tags table manually with @command{etags}.
>  * Etags Regexps::       Create arbitrary tags using regular expressions.
>  @end menu

Please don't change the order of the sections.  "Create" should
precede "update", since the regen feature is optional.  If this order
requires some changes in how the text is written, please make those
changes, but putting "update" before "create" is illogical.  Also, the
description of "update" says "create", which is another brow-raising
factor.

> +@node Update Tags Table
> +@subsubsection Keeping Tags Tables up to date
> +
> +   The easiest way to manage tags tables is by enabling
> +@code{etags-regen-mode} (@kbd{M-x etags-regen-mode RET}).

It is too early to say this, because if we do, people will ask why
that mode is not turned on by default.  We may turn it on by default
some day (and then the text will need to be rearranged or rewritten),
but we are not there yet, so let's please not put the cart before the
horse, and let's describe etags-regen-mode as what it is: an optional
minor mode that was just added, and should yet withstand the test of
time before we consider recommending it as _the_ primary MO.

> +Note that this feature disables itself if you have already manually
> +visited a tags table (with @kbd{M-x visit-tags-table}, or through an
> +explicit prompt triggered by some feature that requires tags).

This aspect is IMO somewhat problematic.  I wasn't aware of it, and
now that I read this, I'm not sure it is correct and will meet user
expectations.