Instead of just linking to the information, which may be removed in the future, you could have also pasted a snippet of a relevant section. Like:
If --force is specified twice, the operation is immediately executed without terminating any processes or unmounting any file systems. This may result in data loss. Note that when --force is specified twice the halt operation is executed by systemctl itself, and the system manager is not contacted. This means the command should succeed even when the system manager has crashed.