bug#38181: Actual height of mode-line not taken into account

[Eli Zaretskii]

> Cc: 38181@debbugs.gnu.org
> From: martin rudalics <rudalics@gmx.at>
> Date: Sat, 16 Nov 2019 20:30:55 +0100
> 
>  > However, if after
>  > calling display_mode_lines we detect that the height of the mode line
>  > changed, we schedule an immediate thorough redisplay.
> 
> ... which, unfortunately, will not re-run ‘fit-window-to-buffer’ but
> just use its earlier computed values.

Maybe fit-window-to-buffer should set some hook, which redisplay
should call if it finds out that the mode-line height changed?