Normaly that would be the original file and the one I suggested editing is a symbolic link to that:
/etc/systemd/system/sockets.target.wants/docker.socket
Make sure it is true:
ls -la /etc/systemd/system/sockets.target.wants/docker.socket
You can try to stop the docker socket and also disable it, then edit the original file, reenable it and start docker again after reloading the systemd daemon
systemctl stop docker
systemctl stop docker.socket
systemctl disable docker.socket
# Edit the file at this point
systemctl daemon-reload
systemctl enable docker.socket
systemctl start docker.socket
systemctl start docker
You can also check the file before each step to see when it i changed if it will be changed again.