Documentation: lacking reference to systemctl command on PXC add-node page

When bootstrapping a node, we have both ways of starting the service documented (https://www.percona.com/doc/percona-xtradb-cluster/5.7/bootstrap.html):
 
[root@pxc1 ~]# /etc/init.d/mysql bootstrap-pxc
 and
[root@pxc1 ~]# systemctl start mysql@bootstrap.service 
 
However, when adding other nodes, we only have reference for init.d command (https://www.percona.com/doc/percona-xtradb-cluster/5.7/add-node.html):
 
[root@pxc2 ~]# /etc/init.d/mysql start 
 
We should add:
 
[root@pxc2 ~]# systemctl start mysql
 
 
The same with the "starting the third node section" (https://www.percona.com/doc/percona-xtradb-cluster/5.7/add-node.html#starting-the-third-node)