bug#66317: Project mode-line

[Juri Linkov]

>>>> Agreed.  No need to support it in older versions.  Moreover,
>>>> I'm trying to add another option to join project and vc indicators
>>>> on the mode-line that won't be possible to support in older versions.
>>> Then that needs to be explained in the docstring. project.el is installable
>>> in older versions.
>> Hopefully I explained this sufficiently well in the docstring
>> both for users of older versions and users who customized the
>> default mode line.
>
> Not sure: I imagine that most users don't customize mode-line-format
> themselves, and thus don't know which contents it has.
>
> I would append some clarification that in Emacs 30 the mode-line has that
> element by default.

I'm not sure if this helps because a user might run Emacs 30
and still using some package that heavily modifies the mode line.
This will puzzle the user: why it doesn't work in Emacs 30
as documented.