bug#51321: 29.0.50; date in modelines

[Eli Zaretskii]

> Date: Sat, 30 Oct 2021 19:09:51 +0100
> From: Alan Third <alan@idiocy.org>
> Cc: Lars Ingebrigtsen <larsi@gnus.org>, nisoni@algon.dk, 
> 51321@debbugs.gnu.org,
> IIRC there was some concern when we made this change that there might
> have been confusion caused by it, but afaict we've never had any
> problems. Therefore I don't think there's any good reason not to
> extend it this way.
> 
> That was a long way of saying looks good to me.

Thanks.  On which branch would you recommend to install this?