bug#51247: 28.0.60; Insufficient documentation of tab-bar.el internal functions

[Juri Linkov]

>> You don't need to explain about buttons that drop a menu.
>> This is irrelevant for the description of tab-bar-format.
>> Just imagine there is no tab-bar-format-menu-global
>> that uses own unrelated menu items.
>
> Sorry, that won't fly.  The doc string should explain enough for other
> Lisp programmers to be able to produce buttons that drop down menus.

This is the whole point.  The doc string of this variable is not an
appropriate place to teach Lisp programmers how to produce buttons
that drop down menus.  Or you might as well include the whole
Emacs Lisp Reference Manual in this doc string.

> So please humor me with a detailed enough answer to my questions, I'm
> investing enough energy in this stuff to be entitled to a bit more
> than a couple of dismissive sentences.
>
> We must have a decent doc string for this defcustom.  Please help me
> fix what we have now.

You assumed in the doc string that those menu items as used
to display a menu, whereas in fact those menu items as used
to display tabs and other buttons on the tab bar.