Deb: Correct documentation about systemd using debian-start

The mariadb.service systemd file indeed does contain:
  ExecStartPost=/etc/mysql/debian-start

So don't claim it does not use debian-start.

Upstreamed from https://salsa.debian.org/mariadb-team/mariadb-10.5/-/commit/af869e703014b25795b0891e3450520c599d3650

debian/additions/debian-start

 #!/bin/bash
 #
-# This script is executed by "/etc/init.d/mariadb" on every (re)start.
+# This script is executed by both SysV init /etc/init.d/mariadb and
+# systemd mariadb.service on every (re)start.
 #
 # Changes to this file will be preserved when updating the Debian package.
 #
-# NOTE: This file is read only by the traditional SysV init script, not systemd.
-#
 
 source /usr/share/mysql/debian-start.inc.sh
 

debian/mariadb-server-10.5.mysql.default

@@ -10,8 +10,7 @@
 # https://wiki.debian.org/Teams/pkg-systemd/Packaging#overriding_options_and_.2Fetc.2Fdefault_handling
 # https://mariadb.com/kb/en/mariadb/systemd/
 #
-# Note also that MariaDB systemd does _not_ utilize mysqld_safe nor debian-start.
-
+# Note also that MariaDB systemd does _not_ utilize mysqld_safe.
 
 # The delay in seconds the init script waits for the server to be up and running after having started "mysqld_safe" to run the "/etc/mysql/debian-start" script.
 # If the server is still not responding after the delay, the script won't be executed and an error will be thrown on the syslog.