Bug#1110184: release-notes: document /etc/sysctl.conf being dropped

The /etc/sysctl.d/99-sysctl.conf symlink got dropped from the systemd
package in version 256.4-1 following
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1076190

The package search also results no package containing that file in
trixie. What package do I need to install to get the symlink? As far as
I can see it is just gone. This seems to be specific to that config file
and I think it should just be documented in the release notes. Anyone
who changes kernel parameters in /etc/sysctl.conf instead of following
the modern systemd way of using /etc/sysctl.conf.d/ will have their
changes silently dropped by the upgrade.